I wrote a simlar post in Bitcoin about creating a MS wallet without a Trezor, this guide will focus on creating a 3of3 MS wallet with three Trezor's. Hopefully it should be obvious how to extend this to N-of-M for any value of N or M. You can also use this as a blueprint to do MS with non-HW Electrum wallets like Android.
It should be noted that this is the most general case method for setting this up. This allows to replace non-HW Electrum wallets into this procedure where HW-wallets are referenced. For the far simpler method, just pick Cosign with hardware device instead of Cosign with key as I outline here. If you choose Cosign with HW you can do the entire process in one wallet file in one session.
The main advantage of multisig is that it reduces the risk of one compromised seed exposing all your funds. Although this is exceedingly complicated, the added layer of complications make it all the more difficult to compromise your funds. Most of the complexity is on the initial wallet setup. Sending is only a bit more complicated, and Receiving is the same as it would be for any electrum wallet.
We will be creating three wallets here, and each will use a Trezor with its own seed, passphrase, and public key (Zpub). If your just wanting to play with this process you could use one Trezor with three different passphrases. Electrum will treat this like three different wallets, since... well since it is. The Zpubs will be calculated by Electrum.
For all references to wallet passphrases or encryption passwords, I highly recommend you generate six-word passphrases. Three simple ways to construct a six-word passphrase would be to either use EFF diceware long wordlist to roll for 6 words, or create a short six-word BIP39 seed and use that as a passphrase, or create a random Electrum seed and use the last 6 words. You will need to take care that all six-word passphrases are equal or less than 50 characters. Longer passphrases can produce some unexpected results. Whenever you need to create a passphrase or password from here on out, create a six-word string as described above.
Assuming your have your Trezors initialized with passphrases enabled, our first order of business will be ensuring the authenticity of Electrum. For the PC's this must be done with PGP/GPG following the procedure spelled out on the Electrum website, or the secondary docs. It is absolutely critical that you are certain your using the correct ThomasV key. As of the time of this writing, the "correct" ThomasV key was:
ThomasV PGP: 6694 D8DE 7BE8 EE56 31BE D950 2BD5 824B 7F94 70E6
Once your Electrum install is validated, here is excruciating detail on creating and spending from a 3of3 multisig wallet. This assumes you have passphrases enabled on all your Trezors and that each has a unique name. For simplicity I will simply refer to their names at "trez-1", "trez-2", and "trez-3"

Three Wallet Creation passes

Do the following first for "trez-1", then for "trez-2" and finally for "trez-3". The order is VERY important:

1. Wallet->New, name your wallet
2. Then insert your Trezor ("trez-1", "trez-2", or "trez-3")
3. Choose Multisig Wallet, then 3of3
4. Choose Use a hardware device
5. Select device
6. Craft (and record) a new 6 word passphrase
7. Choose Native Segwit derivation
8. Record Zpub
9. Unplug your Trezor ("trez-1", "trez-2", or "trez-3")
10. Choose Add Cosigner Key
11. Wait at "Add Cosigner 2" dialog

Distribute Zpubs to Finish Wallet Creation

When completing the setup for each wallet below you will be prompted for a wallet encryption password. I recommend you craft a unique six-word string as described above. If Electrum asks to reconnect to your HW wallet simply say "No". You will notice that the order is the reverse of the previous portion. As before, the order is VERY important,.

1. Swap over to your trez-3 wallet
2. Click "Enter Cosigner Key"
3. Enter trez-1 Zpub
4. Click "Enter Cosigner Key"
5. Enter trez-2 Zpub
6. Swap over to your trez-2 wallet
7. Click "Enter Cosigner Key"
8. Enter trez-3 Zpub
9. Click "Enter Cosigner Key"
10. Enter trez-1 Zpub
11. Swap over to your trez-1 wallet
12. Click "Enter Cosigner Key"
13. Enter trez-2 Zpub
14. Click "Enter Cosigner Key"
15. Enter trez-3 Zpub

You can now close each wallet file.
You should now have recorded:

• 3 Trezor mnemonic seeds
• 3 Trezor six-word passphrases (less than 50 chars)
• 3 Electrum Zpubs
• 3 Wallet encryption "passwords" (six-word strings described above)

Keep the 12 secrets secure, separate and safe.

Receive funds into your 3of3 MS wallet

Receive just like any other wallet. All three wallets will watch the same set of addresses

Spend funds from your 3of3 MS wallet

1. Create a TXN as you normally would on your first device
2. In the TXN dialog hit "Preview" instead of Send
3. In the Preview screen hit "Sign", then "Export"
4. Copy the TXN over to your second device
5. On your second device click Tools->Load Transaction
6. Enter your partially signed TXN
7. Verify the Status reads "Partially signed (1/3)"
8. In the Preview screen hit "Sign", then "Export"
9. Copy the TXN over to your third device
10. On your third device click Tools->Load Transaction
11. Enter your partially signed TXN
12. Verify the Status reads "Partially signed (2/3)"
13. In the Preview screen hit "Sign", then "Broadcast"

Conclusion

Certainly more complicated than a non MS wallet, but a lot more secure. Also be aware that the Segwit MS TXNs are about 40% larger than the native Segwit TXNs, so this does generate some additional cost in TXN fees.

good news, everybody!
This is my first post on Reddit and it's in fact a repost from another blogging platform where I activate already.
I was excited since I saw this announcement and I thought to myself what kind of approach should have for this kind of story, but the time passed and nothing brilliant came in my mind and then I figured that the simple things are the best.
So: what are you saying about not being necessary anymore to use or remember a password for logging into different services from websites?
Just remember you have to make online payments, log into your streaming providers, games, utility services, etc. Instead of filling every time a password, you will be able to receive a QR code which will allow to make the login possible.
Look what the Marty Bent podcaster said:

“No more remembering unique passwords for separate sites. No more creating unique email addresses for different services. No more having to worry about the site you are interacting with having your data stolen from them. Pure, self-sovereign control of your accounts across the Internet. No usernames, passwords, or identifying information other than the public key that is derived upon sign up.”

There are more solutions that I discovered:

1. LNURL protocol
   
2. MyDigiPassword - from digibyte development
   
3. SQRL
   
4. WebAuthn
   
5. BitID
   

If the firts two seems to be more reliable, the last three has some flaws, like vulnerability of anti phishing attacks (for SQRL and BitID) or too complex (WebAuthn). The time will demonstrate which is the best.
In two words (rather minutes), this is how it works:
https://youtu.be/XncWhLni-Ok
Let's see what LNURL people says about it:

The basic idea is that each wallet has a seed, which is a random value (you may think of the BIP39 seed words, for example). Usually from that seed different keys are derived, each of these yielding a Bitcoin address, and also from that same seed may come the keys used to generate and manage Lightning channels. What lnurl-auth does is to generate a new key from that seed, and from that a new key for each service (identified by its domain) you try to authenticate with.

So, from the seed of your wallet will be generated different keys for your different websites you access, so nobody will now you are the same person using all of this services.
I hope this material was useful.
If not, please do a comment, it will help me to develop myself in the future

Introduction

Dear Groestlers, it goes without saying that 2020 has been a difficult time for millions of people worldwide. The groestlcoin team would like to take this opportunity to wish everyone our best to everyone coping with the direct and indirect effects of COVID-19. Let it bring out the best in us all and show that collectively, we can conquer anything.
The centralised banks and our national governments are facing unprecedented times with interest rates worldwide dropping to record lows in places. Rest assured that this can only strengthen the fundamentals of all decentralised cryptocurrencies and the vision that was seeded with Satoshi's Bitcoin whitepaper over 10 years ago. Despite everything that has been thrown at us this year, the show must go on and the team will still progress and advance to continue the momentum that we have developed over the past 6 years.
In addition to this, we'd like to remind you all that this is Groestlcoin's 6th Birthday release! In terms of price there have been some crazy highs and lows over the years (with highs of around $2.60 and lows of $0.000077!), but in terms of value– Groestlcoin just keeps getting more valuable! In these uncertain times, one thing remains clear – Groestlcoin will keep going and keep innovating regardless. On with what has been worked on and completed over the past few months.

UPDATED - Groestlcoin Core 2.18.2

This is a major release of Groestlcoin Core with many protocol level improvements and code optimizations, featuring the technical equivalent of Bitcoin v0.18.2 but with Groestlcoin-specific patches. On a general level, most of what is new is a new 'Groestlcoin-wallet' tool which is now distributed alongside Groestlcoin Core's other executables.
NOTE: The 'Account' API has been removed from this version which was typically used in some tip bots. Please ensure you check the release notes from 2.17.2 for details on replacing this functionality.

• Builds are now done through Gitian
• Calls to getblocktemplate will fail if the segwit rule is not specified. Calling getblocktemplate without segwit specified is almost certainly a misconfiguration since doing so results in lower rewards for the miner. Failed calls will produce an error message describing how to enable the segwit rule.
• A warning is printed if an unrecognized section name is used in the configuration file. Recognized sections are [test], [main], and [regtest].
• Four new options are available for configuring the maximum number of messages that ZMQ will queue in memory (the "high water mark") before dropping additional messages. The default value is 1,000, the same as was used for previous releases.
• The rpcallowip option can no longer be used to automatically listen on all network interfaces. Instead, the rpcbind parameter must be used to specify the IP addresses to listen on. Listening for RPC commands over a public network connection is insecure and should be disabled, so a warning is now printed if a user selects such a configuration. If you need to expose RPC in order to use a tool like Docker, ensure you only bind RPC to your localhost, e.g. docker run [...] -p 127.0.0.1:1441:1441 (this is an extra :1441 over the normal Docker port specification).
• The rpcpassword option now causes a startup error if the password set in the configuration file contains a hash character (#), as it's ambiguous whether the hash character is meant for the password or as a comment.
• The whitelistforcerelay option is used to relay transactions from whitelisted peers even when not accepted to the mempool. This option now defaults to being off, so that changes in policy and disconnect/ban behavior will not cause a node that is whitelisting another to be dropped by peers.
• A new short about the JSON-RPC interface describes cases where the results of anRPC might contain inconsistencies between data sourced from differentsubsystems, such as wallet state and mempool state.
• A new document (https://github.com/groestlcoin/groestlcoin/blob/mastedoc/groestlcoin-conf.md) about the groestlcoin.conf file describes how to use it to configure Groestlcoin Core.
• A new document introduces Groestlcoin Core's BIP174 interface, which is used to allow multiple programs to collaboratively work to create, sign, and broadcast new transactions. This is useful for offline (cold storage) wallets, multisig wallets, coinjoin implementations, and many other cases where two or more programs need to interact to generate a complete transaction.
• The output script descriptor (https://github.com/groestlcoin/groestlcoin/blob/mastedoc/descriptors.md) documentation has been updated with information about new features in this still-developing language for describing the output scripts that a wallet or other program wants to receive notifications for, such as which addresses it wants to know received payments. The language is currently used in multiple new and updated RPCs described in these release notes and is expected to be adapted to other RPCs and to the underlying wallet structure.
• A new --disable-bip70 option may be passed to ./configure to prevent Groestlcoin-Qt from being built with support for the BIP70 payment protocol or from linking libssl. As the payment protocol has exposed Groestlcoin Core to libssl vulnerabilities in the past, builders who don't need BIP70 support are encouraged to use this option to reduce their exposure to future vulnerabilities.
• The minimum required version of Qt (when building the GUI) has been increased from 5.2 to 5.5.1 (the depends system provides 5.9.7)
• getnodeaddresses returns peer addresses known to this node. It may be used to find nodes to connect to without using a DNS seeder.
• listwalletdir returns a list of wallets in the wallet directory (either the default wallet directory or the directory configured bythe -walletdir parameter).
• getrpcinfo returns runtime details of the RPC server. Currently, it returns an array of the currently active commands and how long they've been running.
• deriveaddresses returns one or more addresses corresponding to an output descriptor.
• getdescriptorinfo accepts a descriptor and returns information aboutit, including its computed checksum.
• joinpsbts merges multiple distinct PSBTs into a single PSBT. The multiple PSBTs must have different inputs. The resulting PSBT will contain every input and output from all the PSBTs. Any signatures provided in any of the PSBTs will be dropped.
• analyzepsbt examines a PSBT and provides information about what the PSBT contains and the next steps that need to be taken in order to complete the transaction. For each input of a PSBT, analyze psbt provides information about what information is missing for that input, including whether a UTXO needs to be provided, what pubkeys still need to be provided, which scripts need to be provided, and what signatures are still needed. Every input will also list which role is needed to complete that input, and analyzepsbt will also list the next role in general needed to complete the PSBT. analyzepsbt will also provide the estimated fee rate and estimated virtual size of the completed transaction if it has enough information to do so.
• utxoupdatepsbt searches the set of Unspent Transaction Outputs (UTXOs) to find the outputs being spent by the partial transaction. PSBTs need to have the UTXOs being spent to be provided because the signing algorithm requires information from the UTXO being spent. For segwit inputs, only the UTXO itself is necessary. For non-segwit outputs, the entire previous transaction is needed so that signers can be sure that they are signing the correct thing. Unfortunately, because the UTXO set only contains UTXOs and not full transactions, utxoupdatepsbt will only add the UTXO for segwit inputs.
• getpeerinfo now returns an additional minfeefilter field set to the peer's BIP133 fee filter. You can use this to detect that you have peers that are willing to accept transactions below the default minimum relay fee.
• The mempool RPCs, such as getrawmempool with verbose=true, now return an additional "bip125-replaceable" value indicating whether thetransaction (or its unconfirmed ancestors) opts-in to asking nodes and miners to replace it with a higher-feerate transaction spending any of the same inputs.
• settxfee previously silently ignored attempts to set the fee below the allowed minimums. It now prints a warning. The special value of"0" may still be used to request the minimum value.
• getaddressinfo now provides an ischange field indicating whether the wallet used the address in a change output.
• importmulti has been updated to support P2WSH, P2WPKH, P2SH-P2WPKH, and P2SH-P2WSH. Requests for P2WSH and P2SH-P2WSH accept an additional witnessscript parameter.
• importmulti now returns an additional warnings field for each request with an array of strings explaining when fields are being ignored or are inconsistent, if there are any.
• getaddressinfo now returns an additional solvable Boolean field when Groestlcoin Core knows enough about the address's scriptPubKey, optional redeemScript, and optional witnessScript for the wallet to be able to generate an unsigned input spending funds sent to that address.
• The getaddressinfo, listunspent, and scantxoutset RPCs now return an additional desc field that contains an output descriptor containing all key paths and signing information for the address (except for the private key). The desc field is only returned for getaddressinfo and listunspent when the address is solvable.
• importprivkey will preserve previously-set labels for addresses or public keys corresponding to the private key being imported. For example, if you imported a watch-only address with the label "coldwallet" in earlier releases of Groestlcoin Core, subsequently importing the private key would default to resetting the address's label to the default empty-string label (""). In this release, the previous label of "cold wallet" will be retained. If you optionally specify any label besides the default when calling importprivkey, the new label will be applied to the address.
• getmininginfo now omits currentblockweight and currentblocktx when a block was never assembled via RPC on this node.
• The getrawtransaction RPC & REST endpoints no longer check the unspent UTXO set for a transaction. The remaining behaviors are as follows:
  1. If a blockhash is provided, check the corresponding block.
  2. If no blockhash is provided, check the mempool.
  3. If no blockhash is provided but txindex is enabled, also check txindex.
• unloadwallet is now synchronous, meaning it will not return until the wallet is fully unloaded.
• importmulti now supports importing of addresses from descriptors. A desc parameter can be provided instead of the "scriptPubKey" in are quest, as well as an optional range for ranged descriptors to specify the start and end of the range to import. Descriptors with key origin information imported through importmulti will have their key origin information stored in the wallet for use with creating PSBTs.
• listunspent has been modified so that it also returns witnessScript, the witness script in the case of a P2WSH orP2SH-P2WSH output.
• createwallet now has an optional blank argument that can be used to create a blank wallet. Blank wallets do not have any keys or HDseed. They cannot be opened in software older than 2.18.2. Once a blank wallet has a HD seed set (by using sethdseed) or private keys, scripts, addresses, and other watch only things have been imported, the wallet is no longer blank and can be opened in 2.17.2. Encrypting a blank wallet will also set a HD seed for it.
• signrawtransaction is removed after being deprecated and hidden behind a special configuration option in version 2.17.2.
• The 'account' API is removed after being deprecated in v2.17.2 The 'label' API was introduced in v2.17.2 as a replacement for accounts. See the release notes from v2.17.2 for a full description of the changes from the 'account' API to the 'label' API.
• addwitnessaddress is removed after being deprecated in version 2.16.0.
• generate is deprecated and will be fully removed in a subsequent major version. This RPC is only used for testing, but its implementation reached across multiple subsystems (wallet and mining), so it is being deprecated to simplify the wallet-node interface. Projects that are using generate for testing purposes should transition to using the generatetoaddress RPC, which does not require or use the wallet component. Calling generatetoaddress with an address returned by the getnewaddress RPC gives the same functionality as the old generate RPC. To continue using generate in this version, restart groestlcoind with the -deprecatedrpc=generate configuration option.
• Be reminded that parts of the validateaddress command have been deprecated and moved to getaddressinfo. The following deprecated fields have moved to getaddressinfo: ismine, iswatchonly,script, hex, pubkeys, sigsrequired, pubkey, embedded,iscompressed, label, timestamp, hdkeypath, hdmasterkeyid.
• The addresses field has been removed from the validateaddressand getaddressinfo RPC methods. This field was confusing since it referred to public keys using their P2PKH address. Clients should use the embedded.address field for P2SH or P2WSH wrapped addresses, and pubkeys for inspecting multisig participants.
• A new /rest/blockhashbyheight/ endpoint is added for fetching the hash of the block in the current best blockchain based on its height (how many blocks it is after the Genesis Block).
• A new Window menu is added alongside the existing File, Settings, and Help menus. Several items from the other menus that opened new windows have been moved to this new Window menu.
• In the Send tab, the checkbox for "pay only the required fee" has been removed. Instead, the user can simply decrease the value in the Custom Fee rate field all the way down to the node's configured minimumrelay fee.
• In the Overview tab, the watch-only balance will be the only balance shown if the wallet was created using the createwallet RPC and thedisable_private_keys parameter was set to true.
• The launch-on-startup option is no longer available on macOS if compiled with macosx min version greater than 10.11 (useCXXFLAGS="-mmacosx-version-min=10.11" CFLAGS="-mmacosx-version-min=10.11" for setting the deployment sdkversion)
• A new groestlcoin-wallet tool is now distributed alongside Groestlcoin Core's other executables. Without needing to use any RPCs, this tool can currently create a new wallet file or display some basic information about an existing wallet, such as whether the wallet is encrypted, whether it uses an HD seed, how many transactions it contains, and how many address book entries it has.
• Since version 2.16.0, Groestlcoin Core's built-in wallet has defaulted to generating P2SH-wrapped segwit addresses when users want to receive payments. These addresses are backwards compatible with all widely used software. Starting with Groestlcoin Core 2.20.1 (expected about a year after 2.18.2), Groestlcoin Core will default to native segwitaddresses (bech32) that provide additional fee savings and other benefits. Currently, many wallets and services already support sending to bech32 addresses, and if the Groestlcoin Core project sees enough additional adoption, it will instead default to bech32 receiving addresses in Groestlcoin Core 2.19.1. P2SH-wrapped segwit addresses will continue to be provided if the user requests them in the GUI or by RPC, and anyone who doesn't want the update will be able to configure their default address type. (Similarly, pioneering users who want to change their default now may set the addresstype=bech32 configuration option in any Groestlcoin Core release from 2.16.0 up.)
• BIP 61 reject messages are now deprecated. Reject messages have no use case on the P2P network and are only logged for debugging by most network nodes. Furthermore, they increase bandwidth and can be harmful for privacy and security. It has been possible to disable BIP 61 messages since v2.17.2 with the -enablebip61=0 option. BIP 61 messages will be disabled by default in a future version, before being removed entirely.
• The submitblock RPC previously returned the reason a rejected block was invalid the first time it processed that block but returned a generic "duplicate" rejection message on subsequent occasions it processed the same block. It now always returns the fundamental reason for rejecting an invalid block and only returns "duplicate" for valid blocks it has already accepted.
• A new submitheader RPC allows submitting block headers independently from their block. This is likely only useful for testing.
• The signrawtransactionwithkey and signrawtransactionwithwallet RPCs have been modified so that they also optionally accept a witnessScript, the witness script in the case of a P2WSH orP2SH-P2WSH output. This is compatible with the change to listunspent.
• For the walletprocesspsbt and walletcreatefundedpsbt RPCs, if thebip32derivs parameter is set to true but the key metadata for a public key has not been updated yet, then that key will have a derivation path as if it were just an independent key (i.e. no derivation path and its master fingerprint is itself).
• The -usehd configuration option was removed in version 2.16.0 From that version onwards, all new wallets created are hierarchical deterministic wallets. This release makes specifying -usehd an invalid configuration option.
• This release allows peers that your node automatically disconnected for misbehaviour (e.g. sending invalid data) to reconnect to your node if you have unused incoming connection slots. If your slots fill up, a misbehaving node will be disconnected to make room for nodes without a history of problems (unless the misbehaving node helps your node in some other way, such as by connecting to a part of the Internet from which you don't have many other peers). Previously, Groestlcoin Core banned the IP addresses of misbehaving peers for a period (default of 1 day); this was easily circumvented by attackers with multiple IP addresses. If you manually ban a peer, such as by using the setban RPC, all connections from that peer will still be rejected.
• The key metadata will need to be upgraded the first time that the HDseed is available. For unencrypted wallets this will occur on wallet loading. For encrypted wallets this will occur the first time the wallet is unlocked.
• Newly encrypted wallets will no longer require restarting the software. Instead such wallets will be completely unloaded and reloaded to achieve the same effect.
• A sub-project of Bitcoin Core now provides Hardware Wallet Interaction (HWI) scripts that allow command-line users to use several popular hardware key management devices with Groestlcoin Core. See their project page for details.
• This release changes the Random Number Generator (RNG) used from OpenSSL to Groestlcoin Core's own implementation, although entropy gathered by Groestlcoin Core is fed out to OpenSSL and then read back in when the program needs strong randomness. This moves Groestlcoin Core a little closer to no longer needing to depend on OpenSSL, a dependency that has caused security issues in the past. The new implementation gathers entropy from multiple sources, including from hardware supporting the rdseed CPU instruction.
• On macOS, Groestlcoin Core now opts out of application CPU throttling ("app nap") during initial blockchain download, when catching up from over 100 blocks behind the current chain tip, or when reindexing chain data. This helps prevent these operations from taking an excessively long time because the operating system is attempting to conserve power.

How to Upgrade?

Windows
If you are running an older version, shut it down. Wait until it has completely shut down (which might take a few minutes for older versions), then run the installer.
OSX
If you are running an older version, shut it down. Wait until it has completely shut down (which might take a few minutes for older versions), run the dmg and drag Groestlcoin Core to Applications.
Ubuntu
http://groestlcoin.org/forum/index.php?topic=441.0

Other Linux

http://groestlcoin.org/forum/index.php?topic=97.0

Download

Download the Windows Installer (64 bit) here
Download the Windows Installer (32 bit) here
Download the Windows binaries (64 bit) here
Download the Windows binaries (32 bit) here
Download the OSX Installer here
Download the OSX binaries here
Download the Linux binaries (64 bit) here
Download the Linux binaries (32 bit) here
Download the ARM Linux binaries (64 bit) here
Download the ARM Linux binaries (32 bit) here

Source

ALL NEW - Groestlcoin Moonshine iOS/Android Wallet

Built with React Native, Moonshine utilizes Electrum-GRS's JSON-RPC methods to interact with the Groestlcoin network.
GRS Moonshine's intended use is as a hot wallet. Meaning, your keys are only as safe as the device you install this wallet on. As with any hot wallet, please ensure that you keep only a small, responsible amount of Groestlcoin on it at any given time.

Features

• Groestlcoin Mainnet & Testnet supported
• Bech32 support
• Multiple wallet support
• Electrum - Support for both random and custom peers
• Encrypted storage
• Biometric + Pin authentication
• Custom fee selection
• Import mnemonic phrases via manual entry or scanning
• RBF functionality
• BIP39 Passphrase functionality
• Support for Segwit-compatible & legacy addresses in settings
• Support individual private key sweeping
• UTXO blacklisting - Accessible via the Transaction Detail view, this allows users to blacklist any utxo that they do not wish to include in their list of available utxo's when sending transactions. Blacklisting a utxo excludes its amount from the wallet's total balance.
• Ability to Sign & Verify Messages
• Support BitID for password-free authentication
• Coin Control - This can be accessed from the Send Transaction view and basically allows users to select from a list of available UTXO's to include in their transaction.
• Ability to Broadcast raw transactions

Download

iOS
Android

Source

ALL NEW! – HODL GRS Android Wallet

HODL GRS connects directly to the Groestlcoin network using SPV mode and doesn't rely on servers that can be hacked or disabled.
HODL GRS utilizes AES hardware encryption, app sandboxing, and the latest security features to protect users from malware, browser security holes, and even physical theft. Private keys are stored only in the secure enclave of the user's phone, inaccessible to anyone other than the user.
Simplicity and ease-of-use is the core design principle of HODL GRS. A simple recovery phrase (which we call a Backup Recovery Key) is all that is needed to restore the user's wallet if they ever lose or replace their device. HODL GRS is deterministic, which means the user's balance and transaction history can be recovered just from the backup recovery key.

Features

• Simplified payment verification for fast mobile performance
• No server to get hacked or go down
• Single backup phrase that works forever
• Private keys never leave your device
• Import password protected paper wallets
• Payment protocol payee identity certification

Download

Main Release (Main Net)
Testnet Release

Source

ALL NEW! – GroestlcoinSeed Savior

Groestlcoin Seed Savior is a tool for recovering BIP39 seed phrases.
This tool is meant to help users with recovering a slightly incorrect Groestlcoin mnemonic phrase (AKA backup or seed). You can enter an existing BIP39 mnemonic and get derived addresses in various formats.
To find out if one of the suggested addresses is the right one, you can click on the suggested address to check the address' transaction history on a block explorer.

Features

• If a word is wrong, the tool will try to suggest the closest option.
• If a word is missing or unknown, please type "?" instead and the tool will find all relevant options.

Live Version (Not Recommended)

https://www.groestlcoin.org/recovery/

Download

https://github.com/Groestlcoin/mnemonic-recovery/archive/master.zip

Source

ALL NEW! – Vanity Search Vanity Address Generator

NOTE: NVidia GPU or any CPU only. AMD graphics cards will not work with this address generator.
VanitySearch is a command-line Segwit-capable vanity Groestlcoin address generator. Add unique flair when you tell people to send Groestlcoin. Alternatively, VanitySearch can be used to generate random addresses offline.
If you're tired of the random, cryptic addresses generated by regular groestlcoin clients, then VanitySearch is the right choice for you to create a more personalized address.
VanitySearch is a groestlcoin address prefix finder. If you want to generate safe private keys, use the -s option to enter your passphrase which will be used for generating a base key as for BIP38 standard (VanitySearch.exe -s "My PassPhrase" FXPref). You can also use VanitySearch.exe -ps "My PassPhrase" which will add a crypto secure seed to your passphrase.
VanitySearch may not compute a good grid size for your GPU, so try different values using -g option in order to get the best performances. If you want to use GPUs and CPUs together, you may have best performances by keeping one CPU core for handling GPU(s)/CPU exchanges (use -t option to set the number of CPU threads).

Features

• Fixed size arithmetic
• Fast Modular Inversion (Delayed Right Shift 62 bits)
• SecpK1 Fast modular multiplication (2 steps folding 512bits to 256bits using 64 bits digits)
• Use some properties of elliptic curve to generate more keys
• SSE Secure Hash Algorithm SHA256 and RIPEMD160 (CPU)
• Multi-GPU support
• CUDA optimisation via inline PTX assembly
• Seed protected by pbkdf2_hmac_sha512 (BIP38)
• Support P2PKH, P2SH and BECH32 addresses
• Support split-key vanity address

Usage

https://github.com/Groestlcoin/VanitySearch#usage

Download

Source

ALL NEW! – Groestlcoin EasyVanity 2020

Groestlcoin EasyVanity 2020 is a windows app built from the ground-up and makes it easier than ever before to create your very own bespoke bech32 address(es) when whilst not connected to the internet.
If you're tired of the random, cryptic bech32 addresses generated by regular Groestlcoin clients, then Groestlcoin EasyVanity2020 is the right choice for you to create a more personalised bech32 address. This 2020 version uses the new VanitySearch to generate not only legacy addresses (F prefix) but also Bech32 addresses (grs1 prefix).

Features

• Ability to continue finding keys after first one is found
• Includes warning on start-up if connected to the internet
• Ability to output keys to a text file (And shows button to open that directory)
• Show and hide the private key with a simple toggle switch
• Show full output of commands
• Ability to choose between Processor (CPU) and Graphics Card (GPU) ( NVidia ONLY! )
• Features both a Light and Dark Material Design-Style Themes
• Free software - MIT. Anyone can audit the code.
• Written in C# - The code is short, and easy to review.

Download

Source

Remastered! – Groestlcoin WPF Desktop Wallet (v2.19.0.18)

Groestlcoin WPF is an alternative full node client with optional lightweight 'thin-client' mode based on WPF. Windows Presentation Foundation (WPF) is one of Microsoft's latest approaches to a GUI framework, used with the .NET framework. Its main advantages over the original Groestlcoin client include support for exporting blockchain.dat and including a lite wallet mode.
This wallet was previously deprecated but has been brought back to life with modern standards.

Features

• Works via TOR or SOCKS5 proxy
• Can use bootstrap.dat format as blockchain database
• Import/Export blockchain to/from bootstrap.dat
• Import wallet.dat from Groestlcoin-qt wallet
• Export wallet to wallet.dat
• Use both groestlcoin-wpf and groestlcoin-qt with the same addresses in parallel. When you send money from one program, the transaction will automatically be visible on the other wallet.
• Rescan blockchain with a simple mouse click
• Works as a full node and listens to port 1331 (listening port can be changed)
• Fast Block verifying, parallel processing on multi-core CPUs
• Mine Groestlcoins with your CPU by a simple mouse click
• All private keys are kept encrypted on your local machine (or on a USB stick)
• Lite - Has a lightweight "thin client" mode which does not require a new user to download the entire Groestlcoin chain and store it
• Free and decentralised - Open Source under GNU license

Remastered Improvements

• Bech32 support
• P2sh support
• Fixed Import/Export to wallet.dat
• Testnet Support
• Rescan wallet option
• Change wallet password option
• Address type and Change type options through *.conf file
• Import from bootstrap.dat - It is a flat, binary file containing Groestlcoin blockchain data, from the genesis block through a recent height. All versions automatically validate and import the file "grs.bootstrap.dat" in the GRS directory. Grs.bootstrap.dat is compatible with Qt wallet. GroestlCoin-Qt can load from it.
• In Full mode file %APPDATA%\Groestlcoin-WPF\GRS\GRS.bootstrap.dat is full blockchain in standard bootstrap.dat format and can be used with other clients.

Download

Source

ALL NEW! – BIP39 Key Tool

Groestlcoin BIP39 Key Tool is a GUI interface for generating Groestlcoin public and private keys. It is a standalone tool which can be used offline.

Features

• Selection options for 3-24 words (simply putting the space separated words in the first word box will also work) along with a bip39 passphrase
• User input for total number of addresses desired
• Creation of P2PKH, P2SH, P2WPKH and P2WSH addresses along with xpriv and xpub as per BIP32 spec, using a word list as the starting point following the BIP39 standard.
• Pre-sets for BIP44, BIP49, BIP84 and BIP141 standards, along with custom user input for derivation path
• Option for Hardened or non-hardened addresses
• Option for Testnet private and public keys
• Output containing derivation path, private key in WIF, integer and hex format, public key address, public point on curve and scriptpubkey
• Results are output in a file titled 'wallet.txt' with the time addresses were generated, along with all information presented onscreen

Download

Windows
Linux :

 pip3 install -r requirements.txt python3 bip39\_gui.py 

Source

ALL NEW! – Electrum Personal Server

Groestlcoin Electrum Personal Server aims to make using Electrum Groestlcoin wallet more secure and more private. It makes it easy to connect your Electrum-GRS wallet to your own full node.
It is an implementation of the Electrum-grs server protocol which fulfils the specific need of using the Electrum-grs wallet backed by a full node, but without the heavyweight server backend, for a single user. It allows the user to benefit from all Groestlcoin Core's resource-saving features like pruning, blocks only and disabled txindex. All Electrum-GRS's feature-richness like hardware wallet integration, multi-signature wallets, offline signing, seed recovery phrases, coin control and so on can still be used, but connected only to the user's own full node.
Full node wallets are important in Groestlcoin because they are a big part of what makes the system be trust-less. No longer do people have to trust a financial institution like a bank or PayPal, they can run software on their own computers. If Groestlcoin is digital gold, then a full node wallet is your own personal goldsmith who checks for you that received payments are genuine.
Full node wallets are also important for privacy. Using Electrum-GRS under default configuration requires it to send (hashes of) all your Groestlcoin addresses to some server. That server can then easily spy on your transactions. Full node wallets like Groestlcoin Electrum Personal Server would download the entire blockchain and scan it for the user's own addresses, and therefore don't reveal to anyone else which Groestlcoin addresses they are interested in.
Groestlcoin Electrum Personal Server can also broadcast transactions through Tor which improves privacy by resisting traffic analysis for broadcasted transactions which can link the IP address of the user to the transaction. If enabled this would happen transparently whenever the user simply clicks "Send" on a transaction in Electrum-grs wallet.
Note: Currently Groestlcoin Electrum Personal Server can only accept one connection at a time.

Features

• Use your own node
• Tor support
• Uses less CPU and RAM than ElectrumX
• Used intermittently rather than needing to be always-on
• Doesn't require an index of every Groestlcoin address ever used like on ElectrumX

Download

Windows
Linux / OSX (Instructions)

Source

UPDATED – Android Wallet 7.38.1 - Main Net + Test Net

The app allows you to send and receive Groestlcoin on your device using QR codes and URI links.
When using this app, please back up your wallet and email them to yourself! This will save your wallet in a password protected file. Then your coins can be retrieved even if you lose your phone.

Changes

• Add confidence messages, helping users to understand the confidence state of their payments.
• Handle edge case when restoring via an external app.
• Count devices with a memory class of 128 MB as low ram.
• Introduce dark mode on Android 10 devices.
• Reduce memory usage of PIN-protected wallets.
• Tapping on the app's version will reveal a checksum of the APK that was installed.
• Fix issue with confirmation of transactions that empty your wallet.

Download

Main Net
Main Net (FDroid)
Test Net

Source

UPDATED – Groestlcoin Sentinel 3.5.06 (Android)

Groestlcoin Sentinel is a great solution for anyone who wants the convenience and utility of a hot wallet for receiving payments directly into their cold storage (or hardware wallets).
Sentinel accepts XPUB's, YPUB'S, ZPUB's and individual Groestlcoin address. Once added you will be able to view balances, view transactions, and (in the case of XPUB's, YPUB's and ZPUB's) deterministically generate addresses for that wallet.
Groestlcoin Sentinel is a fork of Groestlcoin Samourai Wallet with all spending and transaction building code removed.

Changes

• Removed Cryptopia
• Added adaptive icons for Android 8 and above
• Add block book block explorer

Download

Source

UPDATED – P2Pool Test Net

Changes

• Add compatibility for Groestlcoin Core 2.18.2

Download

Pre-Hosted Testnet P2Pool is available via http://testp2pool.groestlcoin.org:21330/static/

Source

The question is provoked by the fact that not all 256-bit numbers are valid private keys. To be valid it must be from 0x1 to 0xFFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE BAAE DCE6 AF48 A03B BFD2 5E8C D036 4140.
Is it possible that some randomly chosen (with dice, for example) mnemonic seed is not valid, because it produces not valid private keys? Is there a protection for this?
I know that Electrum can be configured to accept a random list of words (user-generated) and to ignore the incorrect checksum.
What is the risk something to go wrong by using manually selected words (selected with dice and "Bip39-diceware" for example)?
Edit: I looked through the documentation (BIP32) briefly and looks like I found the answer:

In case parse256(IL) ≥ n or ki = 0, the resulting key is invalid, and one should proceed with the next value for i. (Note: this has probability lower than 1 in 2127.)

So, it looks like there is a protection envisioned by the developers. Whew.
Edit 2: Actually, no.

In practice, this will never happen (the probability is so small we can ignore it), and likely implementations don't even bother checking the condition.

This is scary.
Edit 3: I tested Electrum. See "I successfully imported invalid Bitcoin private key! #5797" on the Github page.
Edit 4: It's not a bug, it's a feature.
SomberNight said on Github:

Effectively, with what we are doing, some group elements have two representations; while most only have one. Your "invalid" key contains a number that is too large to be a group element; but we subtract the group order from it and use that number instead. It's as if you imported the "valid" key in the first place. In fact if you try to export it, we will give you the "valid" one.

"Recovery phrase is not valid"? I can help!
Expert Service available (requiring trust)
If you have an invalid BIP39 seed recovery phrase, I can filter by any public address at which you have received Bitcoin or other cryptocurrencies, be it from Ledger, Trezor, Electrum wallet, Bread wallet, Loaf wallet, whatever. Provide me your partial incorrect mnemonic and a public address associated with it, I can narrow this down to the ONE correct mnemonic. (Note that while a public address would help us narrow it down, even if you do not have an address associated with your seed, I can help.) I can help if you have only some of your words, or your whole recovery phrase yet somehow it is not accessing your funds. If on the other hand you have an invalid AEZEED cipher seed for a Bitcoin Lightning Network wallet, or an invalid or corrupt private key, e.g., for a paper wallet, I can also help resolve this issue. I have helped multiple users on reddit and elsewhere recover their crypto. My fee is 10% of any contents up to 10 BTC, and 5% of any contents above 10 BTC. Unlike other services, there is no lower limit to the value of a wallet I will recover, because I love to do this! Please contact u/E-renter or visit https://recover-my-mnemonic.com/
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Litecoin (LTC): MPcG1htXZdPrvyRenRKoPg8Lft7jijT4hW
Ethereum (ETH): 0x6CC2Cf7df195d2dfB2CAE80b5B1ED223843AfF5c
Ripple (XRP): rHtfLH3Q6NKjxPd23rDmgYMAGuPFfKnVee
Dash (DASH): Xn28i7BbER2r5omSVUPkrdULLckGuymAdD

BIP39 seeds can be generated by rolling dice but the last word must be correct for a valid seed because it partially acts as a checksum.
Finding the last word for 12 word seeds is pretty easy since there are only 16 possible words to try. But for 24 word seeds it increases to 256 possible words. It's easier to calculate it.
I demonstrate here how to do that using a python console without requiring any other program. Obviously this should only be done offline - preferably on a "live boot" system.

1. Generate 24 words from dice rolls using diceware as usual.
   
2. Write down the word index values. Make sure 0-based. Often the word list starts with 1 not 0 - so always subtract 1. You will have a list like this on paper:
   1628,1924,582,1492... etc
   
3. On a safe system, open a python console. In Linux terminal just type python. We need to import two modules. Type, import binascii, hashlib.
   
4. Start the calculation. We'll use 's' as our seed variable. Start with the first index. s=1628. For each additional word index type, s=s*2048+1924 (use your numbers). You can use the up arrow key and edit the index value so it's actually pretty fast entering them.
   
5. When all 24 words have been entered you now can copy/paste this code, which will calculate the checksum, and output the adjusted correct index for the last word.
   

   s=s/256 h=hashlib.sha256(binascii.unhexlify('%064x' % s)).digest().encode('hex') int(('%064x' % s)[-1] + h[:2], 16) % 2048 

6. Look this index up in your word list (remember to add one if it is not 0 based). Replace the last word you rolled with this calculated one. It should now validate in any BIP39 wallet. (type quit() to get out of python)
   

This only takes a few minutes and you can easily see no funny business happens with your seed.
edit - I fixed and formatted better so not off page so much, easier to read.

For a more interactive view of changes, click here
In our current world; bordering on financial chaos, with tariff wars, Brexit and hyperinflation rife, you can count on Groestlcoin to consistently produce innovation that strikes to take the power away from the few and into the many, even after a full five and a half years of solid development.
Here is what the team has already announced in the last 3 months since the last development update:

• Added to Ledger Nano X with Electrum-GRS. Offering state-of-the-art security.
• Testnet added to the Ledger Nano X!
• Added to Keepkey hardware wallet with Electrum-GRS.
• Testnet added to Keepkey hardware wallet!
• Added to the new multi-currency wallet, Cobo! With a 12,000 GRS giveaway!
• Groestlcoin Testnet added to ARCHOS Safe-T Mini hardware wallet!
• Groestlcoin started to be accepted at Mind Research & Development!
• Groestlcoin was added to Vertbase cryptocurrency exchange!
• Groestlcoin started to be accepted at Bitcoin-Meister, offering various merchandise.
• Added to the Decentralised Cryptocurrency exchange Neblidex!
• Groestlcoin started to be accepted at Drapis! Offering bee bread, raw honey, comb honey and more!
• BECH32 support added to Binance! Allowing users to withdraw their GRS directly to their Trust Wallet app or any other BECH32-supported app.
• Listed at DynX Decentralised Cryptocurrency Exchange
• Accepted at SpendBTC, offering various giftcards to be purchased with $GRS
• Added to Switchain, a non-custodial cryptocurrency exchange
• Supported at NOWNodes. An innovative platform offering customers unlimited access to public full nodes.
• Groestlcoin added to Melis lite wallet, designed for mobile devices to transact faster than ever.
• Testnet added to Melis lite wallet!
• Supported at NOWPayments, offering instant auto-conversion, easy-to-use API with no hidden fees
• Added to PayCentRUBYdebit card powered by China Union Pay.
• Added to PayCentSapphire debitcard. Powered by Union Pay International!
• Added to PayCent Solitaire debit card, powered by Mastercard!
• See these PayCent cards in action in Korea!
• Added to Digifinex Korea cryptocurrency exchange!
• Accepted at AcceptCryptoz! THE Crypto Directory to find places accepting Crypto near you.
• Added to Cryptwerk! An online directory and map with merchants accepting cryptocurrencies.
• Accepted at 247Bits! Selling cold storage cards and gift cards

What's Being Released Today?

Groestl Nodes

What am I?

Groestl Nodes aims to map out and compare the status of the Groestlcoin mainnet and testnet networks. Even though these networks share the same protocol, there is currently no way to directly compare these coins in a single location. These statistics are essential to evaluate the relative health of both networks.

Features

• Shows Onion (Tor) nodes
• Shows IPv6 nodes
• Supports both main net and test net
• Node Checker – Check the status of a remote node
• Ability to download node data by CSV, JSON or TXT format
• Ability to download unique address data by CSV, JSON or TXT format
• Shows last seen time for each node
• Shows uptime for each node

Source - Website

Groestlcoin Transaction Tool

What am I?

This is a tool for creating unsigned raw Groestlcoin transactions and also to verify existing transactions by entering in the transaction hex and converting this to a human-readable format to verify that a transaction is correct before it is signed.

Features

• Create Raw Unsigned Groestlcoin transactions
• Coin Control
• Generates a QR code for the transaction
• Verifying Transactions
• Compatible with most Groestlcoin wallets including but not restricted to Groestlcoin Core and Electrum-GRS
• Estimates final signed transaction size
• Taking a raw transaction format and shows its Transaction ID, Transaction Inputs and Outputs

Source – Download

Groestlcoin AGCore

What am I?

AGCore is an Android app designed to make it easier to run a Groestlcoin Core node on always-on Android appliances such as set-top boxes, Android TVs and repurposed tablets/phones. If you are a non-technical user of Groestlcoin and want an Android app that makes it easy to run a Groestlcoin Core node by acting as a wrapper, then AG Core is the right choice for you.

What's Changed?

• Update to Groestlcoin Core 2.17.2
• Switched to native builds via NDK for Groestlcoin Core resulting in a smaller footprint.
• Added embedded tor
• Added tor pairing support
• TOR upgrade bug fixes
• Improved blockchain Sync progress using getblockchaininfo verificationprogress
• Improved package download progress bar
• Added support for external storage access > Android M
• Added support for Android Oreo, including new notification mechanism
• Added support for Bitcoind RPC cookie
• Change minimum target to Android 21
• Add support for some arm64 android devices
• Various security and bug fixes

Source - Download

Groestlcoin Electrum

What's Changed?

• Bump Fee (RBF) improvements – Implemented a new fee-bump strategy that can add new inputs, so now any transaction can be fee-bumped. The old strategy was to decrease the value of outputs (starting with change). We will now try the new strategy first, and only use the old as a fallback.
• Coin Choser improvements
  • More likely to construct transactions without change (where possible)
  • Less likely to construct transactions with really small change
  • Only spend negative effective value coins when beneficial for privacy
• Fix long-standing bug that broke wallets with >65k addresses
• Windows binaries: Now build the PyInstaller bootloader ourselves, as this seems to reduce anti-virus false positives
• Fix performance regression for large wallets
• Fix high-DPI issues related to text fields
• Trezor – Allow bypassing 'too old firmware' error
• Trezor – Use only the Bridge to scan devices if it is available
• Hardware wallets – On Win10-1903, some hardware devices with U2F functionality can only be detected with Administrator privileges. A workaround is to run as Admin, or for Trezor to install the Bridge.
• The AppImage Linux x86_64 binary and the Windows setup.exe are now built reproducibly.
• Fix watch-only wallets that could not bump fee in some scenarios
• Faster transaction signing for segwit inputs or really large transactions.

Android Electrum-Specific

• Fix BIP70 payment requests could not be paid
• Allow copy-pasting partial transactions from/to clipboard

OSX – Windows – Windows Standalone – Windows Portable – Linux - Android
Server Source – Server Installer Source – Client Source – Icon Source – Locale Source

Android Wallet – Including Android Wallet Testnet

What am I?

Android Wallet is a BIP-0032 compatible hierarchial deterministic Groestlcoin Wallet, allowing you to send and receive Groestlcoin via QR codes and URI links.

V7.11.1 Changes

• SegWit Support:
  • Send to native SegWit Bech32 addresses.
  • Receive to and spend from native segwit (Bech32) addresses
  • Existing wallets without a spending PIN are updated to use native segwit (Bech32) addresses
  • Existing wallets with spending PIN can be upgraded by changing or removing the PIN
• Add 3 more block explorers – Groestlsight, Blockbook, Blockchair
• New alert for users with insecure Bluetooth
• Use much less memory when displaying QR codes
• Add a warning dialog regarding a relatively high fee
• Clarify message when fetching/validating the payment request fails
• Backing up makes use of the SAF. For most users, this means encrypted backups are stored on Google Drive, but other cloud storage providers can also be used
• Fix certain payments not showing up until they become confirmed
• Always show fiat amounts directly below Groestlcoin value in the payment history
• The QR Code scanner now supports portrait orientation
• Run circular reveal transition if QR code scanner is started via lower action bar
• Update build to Gradle 3.3+ and Android Plugin for Gradle 2.3.3
• Use Room Persistence Library for access to the address book database
• Adds a network security configuration
• Migrate support libraries and architecture components to AndroidX
• Add another backup reminder
• Remove ability to restore backups from list of Base58-encoded private keys
• The app now requires Android 5.0 (Lollipop) or higher
• Option to request coins to a legacy address (Sender may not support BECH32)
• Double the capacity of the block store
• Make more room for transactions list by scrolling away the balance panel
• Based on GroestlcoinJ 0.15.2
• Disconnects from incompatible peers much faster
• Fix crash on Pixel 2 devices
• Fix crash with hyperinflated fiat currencies
• Fix rarely occurring crash when backing up the wallet
• Fix crashes when opening dialogs at the wrong time
• Fix crash when archiving a wallet backup on certain devices
• Updated checkpoints
• Update Electrum-GRS list with server fingerprints
• Removed unused code and features. Show splash icon whilst the app is loading
• Remove labs feature – Look up wallet names from the DNS
• The FOREGROUND_SERVICE permission is now requested (Android 9 Pie +)
• Support notification channels and adaptive launcher icons (Android 8+)
• Fix app shortcuts (Android 7.1)
• Multiple 'coin received' notifications are now bundled into a notification group (Android 7+)

Groestlcoin Java Library Source – Source - Download – Testnet Download

Groestlwallet

What am I?

Groestlwallet is designed to protect you from malware, browser security holes, even physical theft. With AES hardware encryption, app sandboxing, keychain and code signatures, groestlwallet represents a significant security advance over web and desktop wallets, and other mobile platforms.
Simplicity is groestlwallet's core design principle. Because groestlwallet is "deterministic", your balance and entire transaction history can be restored from just your recovery phrase.

iOS 0.7.3 Changes

• Fix BIP70 payments
• Updated QR Scanner
• Lowered spending limit
• Updated DNS Seeds
• Updated checkpoints
• Fixed URL Scheme
• Fixed GRS Name in mailing
• Fixed crash upon starting in some scenarios

Android v89 Changes

• Use default fee
• Republished on Google Play by removing send_sms permissions
• Lowered spending limit
• Updated to API 28
• Use https instead of http for GRS price
• Updated DNS Seeds
• Updated Checkpoints

iOS Source – Android Source - Android Download – iOS Download

Groestlcoinomi Released

What am I?

Groestlcoinomi is a lightweight thin-client Groestlcoin wallet based on a client-server protocol.

Groestlcoinomi v1.1 Desktop Changes

• Rebranded to Groestlcoinomi
• Updated to use ElectrumX 1.4 protocol

Groestlcoinomi Android v1.6 Changes

• Updated to use ElectrumX 1.4 protocol
• Removed unused native code
• Removed local groestlcoinj library (Included from Mavenlocal)
• Updated Gradle

Groestlcoin Java Library Source – Android Source
Android Download – Windows Download – Mac OS Download – Linux Download

Groestlcoin BIP39 Tool

What's Changed?

• Update Samourai Path on BIP32 tab
• Fix BIP38 Support for mainnet and testnet

Source - Download

Hi Bitcoiners!
I’m back with the sixteenth monthly Bitcoin news recap.
It's easy for news and developments to get drowned out by price talk, so each day I pick out the most popularelevant/interesting stories in Bitcoin and save them. At the end of the month I release them in one batch, to give you a quick (but not necessarily the best) overview of what happened in Bitcoin over the past month. Lots of gems this time around!
You can see recaps of the previous months on Bitcoinsnippets.com
A recap of Bitcoin in April 2018

• 01: People unsurprisingly spend the day making April fools jokes about Bitcoin
• 02: A list of all words used to generate 24-word bitcoin seeds with 10⁷² combinations
• 03: The 0.4.1 beta version of Lightning Network implementation Lnd is released
• 04: Mark Karpeles, ex-CEO of Mt. Gox does an AMA & Eclair’s Lightning Network wallet is released for mainnet on Android
• 05: Satoshi Nakamoto chose this date as his birthday as a reference to gold confiscation from US citizens
• 06: Electrum is adding support for the Lightning Network & Nick Szabo on some of the basic concepts of a blockchain 14 years before bitcoin’s release & The SEC allows Bitcoin ETF proposals again & Elizabeth Stark, CEO of Lightning Labs on Yahoo Finance
• 07: People argue over an infographic on technology adoption
• 08: Twitter suspends the @Bitcoin account after it kept tweeting against Bitcoin
• 09: People discuss the value of Technical Analysis for cryptocurrency markets & Someone gets a 1 satoshi tip using the Lightning Network
• 10: People discuss whether Bitcoin is nuanced enough & Canadian banks ban cryptocurrency purchases resulting in skyrocketing volumes on P2P exchanges
• 11: BitMEX research on Proof-of-Stake viability & HalongMining is a 10nm ASIC fabricated by Samsung semiconductors
• 12: The biggest 1hr volume in the history of Bitcoin happens as the price rises $1000 in an hour
• 13: Developers at Chain make Bulletproofs twice as fast & A community member shares content, tools and advice on cryptocurrency and taxes & Yahoo Japan buys a 40% stake in cryptocurrency exchange BitARG
• 14: Bitcoin is declared legal under Islamic law
• 15: Bitcoin reaches 800k subscribers
• 16: A 2-minute reminder of how the banking system works & Coinbase buys Earn.com
• 17: IMF Director Lagarde makes positive comments about cryptocurrencies & Someone is looking to make a Lightning and NFC integration for in-store payments
• 18: Analysis on the age distribution of unspent transaction outputs throughout time
• 19: A reminder that Amazon filed a patent in 2014 to de-anonymize bitcoin transactions and sell the data to law enforcement
• 20: Benedikt Bunz and Pieter Wuille on Bulletproofs & Bitwage integrates SegWit
• 21: The Eclair Lightning Network wallet is improving & A deep dive into Lit: A Lightning Network implementation
• 22: The high court in India is discussing the Bitcoin ban with the Central Bank of India
• 23: The Lightning Network reaches 2000 nodes, $150K capacity and 7000 active channels & Ken Sheriff is repurposing vitage computers to mine bitcoins & You can buy Reddit Gold with bitcoin again
• 24: Exploring the Lightning Network Daemon 0.4 Beta release
• 25: The Nasdaq CEO says they are open to becoming a cryptocurrency exchange & Misleading references get removed from the Bitcoin Wikipedia article
• 26: The 17 millionth Bitcoin has been mined & A guide to using BTCPay, a free and open-source Bitcoin payment processor
• 27: Hundreds of Bitcoin users seek lawsuit against Bitcoin.com for misleading visitors
• 28: Bitcoin was the 9th most read article on Wikipedia in 2017 & France reduces the tax rate on cryptocurrency sales from 45% to 19%
• 29: The government of the Philippines will allow ten cryptocurrency companies to operate in a special economic zone in Cagayan
• 30: Eltoo: a simplified update mechanism for Lightning and off-chain contracts & A beginner’s guide to Lightning on a Raspberry Pi

Last December, in the middle of the 20k bull run, I decided to split the few bitcoins I had into two different wallets; I sent a small fraction to a hot wallet I created, and put the rest into a cold wallet for the future (as savings). I used a 24 word + passphrase approach (BIP39?) for the second wallet; and as you may have guessed, I don't remember the password. When I tried to access it only a few days later, I couldn't. Well, I could, but balance was zero, which means that I had forgotten the password I had used. And no, coins have not been moved, I keep the public address and they're still there. It's just that I can't access them because I'm trying the wrong password, which creates a totally different wallet. At first I panicked, but since 2018 started with a huge drop in value, I just gave up trying to access my lost funds (honestly, entering a bear market made me feel a bit better hehe)...
Anyway, I was just wondering if there is an automated way of trying a bunch of possible passwords faster than doing it manually. At this point, I've assumed I've lost those coins... But just in case.
Note: no, I'm not trying to hack anybody else's wallet. I just want to know if there is any known script or way of testing a huge list of possible passwords to regain access to a lost wallet.
Thanks in advance!

Groestlcoin Dec 2018 Christmas Release Update

As per usual the 3 months has been all hand-on-deck, helping to bring further adoption utilities to Groestlcoin. The markets have been red but as always that doesn't stop the show from going on with regards to the development since the last release update on 24th September. Here's a recap of what has happened so far:

Recap:

• Groestlcoin was added to Changelly. One of the leading Crypto-to-Crypto exchanges that offer some of the best rates on the market – You can also buy with a debit/credit card too and you can buy/sell Groestlcoin directly from your Coinomi wallet, from the website https://groestlcoin.org#exchanges, and you can enable Changelly swaps on your GRSPay stores!
• Groestlcoin was added to the JAXX Liberty wallet! One of the leading multi-crypto wallets in the stores. Safely store your GRS on Android, iOS, Mac OS X, Windows, Linux or Google Chrome. With Jaxx Liberty you are always in control of your private keys, and you can use your wallet on multiple devices. Note: This directly replaces the deprecated JS Wallet which was of a similar (but older) codebase.
• Groestlcoin was integrated into AtomicPay – A decentralised cryptocurrency payment processor that eliminates the involvement of a third-party gateway, allowing merchants to accept payments directly from their customers, with over 2500 merchants already signed up, a public release is set for Mid-January 2019.
• Huobi officially opened trading for Groestlcoin to Korean customers! And in addition, a giveaway of up to 10,000 GRS was held!
• Unocoin ATMs started supporting Groestlcoin at their ATMs, granting the Indian community the ability to withdraw (For INR) and deposit Groestlcoin into their UnoDax account. Groestlcoin $GRS is available on #Unodax exchange with the following pairs: $INR, $TUSD, $BTC.
• Groestlcoin was listed on SWFT BLOCKCHAIN, giving you more opportunities to swap your other altcoins with Groestlcoin or vice versa, quickly and securely.
• Groestlcoin was added to One Page Exchange! Where you can buy and sell Groestlcoin quickly and easily without any form of registration!
• CryptoWolf started accepting VISA, Mastercard and Maesto to buy cryptocurrencies from the CryptoWolf exchange in EUR or USD! Providing a new FIAT gateway to buy Groestlcoin.
• Groestlcoin has been added to CoinZark (Formally VertPig) for fast and efficient Crypto-to-Crypto swaps at very competitive rates using exchange aggregates.
• Groestlcoin was added to PungoWallet! Pungo wallet is built to showcase the features that anyone can achieve with blockchain technology. They have built a set of modular solutions that allow any company to build a blockchain layer to interact with traditional software.
• Groestlcoin was added to StealthEX, offering anonymous cryptocurrency swaps with tens of other coins without disclosing any personal information. Just choose the pairs, enter your address, send your coins and receive your funds!
• Groestlcoin joined InvestFeed, granting a company listing and blue verified badge.
• Groestlcoin was officially added to Blockfolio Signals – For those of you that use Blockfolio, you can keep updated with all the latest news straight from the app, via the Signals icon.
• Groestlcoin has been added to DeltaDirect – Those using Delta can now stay up-to-date with the latest Groestlcoin news, straight from your Delta portfolio tracker app.
• Groestlcoin has been added to CoinGecko Beam – Where you can easily follow us and receive updates without searching through social media.
• Groestlcoin is now live on BitUniverse Link! All of the latest Groestlcoin updates and news will be directly available on BItUniverse.
• Groestlcoin was added to NovaExchange! Launched in 2016 and operating from Sweden, users can trade over 300 different digital assets.
• It come to light that the new Baikal BK-G28 supported the Groestl algorithm, after great lengths of discussion, the core development team decided to not fork away from these ASICs for the near future. If you missed it, a full statement on the subject can be found here: https://medium.com/@groestlcoin/groestlcoin-asic-statement-953f47baee98

What’s New Today?

Groestlcoin on Trezor Model T

As of the latest version of the Trezor Model T firmware, Groestlcoin is now officially supported! The Trezor Model T is the next-generation cryptocurrency hardware wallet, designed to be your universal vault for all of your digital assets. Store and encrypt your coins, passwords and other digital keys with confidence. The Trezor Model T now supports over 500 cryptocurrencies.

Blockbook MainNet & TestNet Block Explorer

Blockbook is an open-source Groestlcoin blockchain explorer with complete REST and websocket APIs that can be used for writing web wallets and other apps that need more advanced blockchain queries than provided by groestlcoind RPC.
Blockbook REST API provides you with a convenient, powerful and simple way to read data from the groestlcoin network and with it, build your own services.

Features:

• Support to broadcast transactions online. Broadcast a raw transaction in hex format over the Groestlcoin network.
• Supports every web browser
• API – Complete REST and Websocket API for querying blocks, transactions and addresses; and receiving live updates
• Light – Thin data model using groestlcoind RPC interface to validate blockchain information. Fast groestlcoind blockchain synchronisation (~1hrs for the entire mainnet), using RocksDB for data storage and optionally raw groestlcoind data files processing.
• Exhaustive – Reports on double spend attempts, outpoint confirmations, outputs spend status reports. Input and Output hyperlinks in transactions. Extended view in transactions to show advanced details.
• Open Source, written in the Go programming language.

Blockbook is available via https://blockbook.groestlcoin.org/ Testnet: https://blockbook-test.groestlcoin.org/ Source code: https://github.com/Groestlcoin/blockbook

Edge Wallet

Groestlcoin has been added to the Edge wallet for Android and iOS. Edge wallet is secure, private and intuitive. By including support for ShapeShift, Simplex and Changelly, Edge allows you to seamlessly shift between digital currencies, anywhere with an internet connection.

Features:

• Multi-Asset Support. Supporting Bitcoin, Ethereum, Groestlcoin and many others, you can safely hold your coins.
• Exchange Support – Supporting Shapeshift, Simplex and Changelly enables the user to seamlessly shift between digital currencies as if you were storing your funds on an exchange.
• In-app buying and selling, exchange your FIAT for cryptocurrency directly within the app.
• Encrypted with a username and password. Seamless login into multiple devices.
• Easy, secure access with PIN or fingerprint. Additionally, supporting 2FA authentication.
• Client-side encryption – All of your data is encrypted on your device before any of your information touches the Edge servers. Being free from server-side hacks and malware means that your assets are as secure as they can be.
• Multi-Platform – Supporting both Android and iOS.

Android: https://play.google.com/store/apps/details?id=co.edgesecure.app
iOS: https://itunes.apple.com/us/app/edge-bitcoin-wallet/id1344400091?mt=8
Direct Android: https://edge.app/app

CoinID Wallet

We are excited to announce that Groestlcoin has been added to CoinID! With integrated cold and hot wallet support, and a host of other unique wallet features, CoinID can easily become your go-to wallet for storing Groestlcoin. More details can be found here: https://coinid.org/s/groestlcoin-wallet-overview.pdf

Features

• Integrated Cold wallet. Store your funds offline and sleep tight at night. All you need is a separate Android or iOS device.
• Transaction Batching – A feature normally reserved for exchanges, CoinID supports transaction batching, allowing the user to group transactions into one, saving space on the blockchain and lowering your transaction fees considerably as a result.
• Complete control – Your private keys never leaves your device. "If you don’t control your private keys, you don’t own your coins".
• SegWit support – Support for Segregated Witness, which means smaller transaction sizes, lower fees, and supporting all 3 address types (grs1, 3, F).
• Hierarchical Deterministic – Use a single set of keys for multiple coins and addresses. When an address is used, a new one is generated.
• Cross-Platform – Built with React Native for rapid development cycles and cross-platform support.

Android: https://play.google.com/store/apps/details?id=org.coinid.wallet.grs
iOS: https://itunes.apple.com/us/app/grs-wallet-for-coinid/id1439638550

Groestlcoin Sentinel - Windows Released

Groestlcoin Sentinel is the easiest and fastest way to track balances of your Groestlcoin addresses.
Features

• No private keys required at all. Sentinel uses only your public addresses to keep track of your balances.
• Capable of holding multiple groestlcoin address with tags, address and their balances.
• Validating each address with Base58_encoding and new Bech32 format for SegWit.
• Using a grid view to show the list, making it easy to add/edit/remove lines at a whim.
• Import addresses in bulk from file, or paste into the textbox (Line separated)
• Using block explorer API services to update balances
• USD value is easy to see from using CoinMarketCap or Chainz.CryptoId.Info APIs
• See the total Groestlcoin amount in BTC, USD and a user-defined local currency.
• Sentinel will automatically attempt to select your local currency, changeable in the settings.
• Automatical refreshing of your balances at regular intervals.

You can download it using the links below.
Download the Windows Wallet (64 bit) here: https://github.com/Groestlcoin/Groestlcoin-Sentinel-Windows/releases/download/1.0/SentinelSetup_x64.msi
Download the Windows Wallet (32 bit) here: https://github.com/Groestlcoin/Groestlcoin-Sentinel-Windows/releases/download/1.0/SentinelSetup_x86.msi
Source code: https://github.com/Groestlcoin/Groestlcoin-Sentinel-Windows/

Groestlcoin BIP39 Tool 0.3.9 Update

The Groestlcoin BIP39 tool is an open-source web tool for converting BIP39 mnemonic codes to addresses and private keys. This enables the greatest security against third-party wallets potentially disappearing – You’ll still have access to your funds thanks to this tool.
What’s New

• Added Coinomi, Ledger Client, Groestlcoinomi, Trezor, Safe T, Core, Groestlpay and Samourai to BIP32 Tab
• Added BIP49 support
• Add BIP38 support
• Add CSV tab for derived addresses
• BIP84 tab for derivation path
• Display version number in top right corner
• Groestlcoin ticker is now also displayed
• Refactor method to clear old data from the display
• BIP44 ‘purpose’ and ‘coin’ fields have been made read only
• Tab Order is now alphabetical
• Improve showing feedback for pending calculations
• Show error when using XPUB with hardened addresses
• Rename variables for clarity between BIP49 and P2WPKH Nested in P2SH
• QR Codes use correctLevel 3 instead of 2
• Update compile script to work across python 2 and 3
• Add BIP49 to More Info section
• Reword entropy text to indicate using a single source only
• Detect and warn when entropy is filtered / discarded
• Use new xpub/xprv prefixes for Segwit BIP49
• Allow more rows to be generated starting from a custom index
• BIP141 tab added for full Segwit compatibility
• Show list of word indexes. Checksum shows in entropy details
• Populate entropy field with hex value used from PRNG
• QR codes with accents now work correctly by replacing jquery.qrcode with kjua
• Allow initial number of rows to be set by the user
• Raw entropy shows groupings with space every 11 bits for easier usage
• Warn that entropy values should exclude checksum
• Warn when generating low entropy mnemonics
• Warn when overriding weak entropy with a strong mnemonic length
• Allow XPUB to be used as root key for Segwit derivations
• Add visual privacy safeguard. List alternative tools
• Update bootstrap from 3.2.0 to 3.3.7 and jQuery from 2.1.1 to 3.2.1
• GroestlcoinJS library upgraded to v3.3.2
• General code refactoring, numerous performance improvements and bug fixes

Download the Groestlcoin BIP39 tool here: https://github.com/Groestlcoin/bip39/archive/master.zip
Source code: https://github.com/groestlcoin/bip39
Or use hosted version: https://groestlcoin.org/bip39/

Electrum-GRS 3.2.3 Update

Electrum-GRS is a lightweight "thin client" Groestlcoin wallet Windows, MacOS and Linux based on a client-server protocol. Its main advantages over the original Groestlcoin client include support for multi-signature wallets and not requiring the download of the entire block chain.
What’s New

• HARDWARE WALLET SUPPORT: Archos Safe-T Mini is now fully supported

Electrum + Android Version 3.2.3:

• If a BIP39 seed extension/passphrase contained multiple consecutive whitespaces or leading/trailing whitespaces, then the derived addresses were not following spec. This has been fixed, and anyone affected should move their codes. The wizard will show a warning in this case.
• The PRNG used has been changed
• Fix Linux distributable, ‘typing’ was not bundled and was required for Python 3.4
• Fix spending from Segwit multi-sig wallets involving a Trezor co-signer when using a custom derivation path.
• Several other minor bugfixes and usability improvements.

Android: https://play.google.com/store/apps/details?id=org.groestlcoin.electrumgrs
Windows & OSX: https://github.com/Groestlcoin/electrum-grs/releases/
Linux:

sudo apt-get install python3-setuptools python3-pyqt5 python3-pip python3-dev libssl-dev sudo pip3 install groestlcoin_hash sudo pip3 install https://github.com/Groestlcoin/electrum-grs/releases/download/v3.2.3/Electrum-grs-3.2.3.tar.gz electrum-grs

GitHub Source server: https://github.com/Groestlcoin/electrumx-grs
Github Source server installer: https://github.com/Groestlcoin/electrumx-grs-installer
Github Source client: https://github.com/Groestlcoin/electrum-grs

Groestlcoin ivendPay Integration

ivendPay and Groestlcoin cryptocurrency have announced the start of integration.
IT company ivendPay, the developer of a universal multicurrency payment module for automatic and retail trade, intends to integrate Groestlcoin cryptocurrency — one of the oldest and the most reputable Bitcoin forks into the payment system. Groestlcoin is characterized by instant transactions with almost zero commission and is optimal for mass retail trade where micropayments are mostly used.
According to Sergey Danilov, founder and CEO of ivendPay, Groestlcoin will become the 11th cryptocurrency integrated into the payment module. The first working vending machines for the sale of coffee, snacks and souvenirs, equipped with ivendPay modules, served the visitors of the CryptoEvent RIW exhibition at VDNKh in Moscow and accepted Bitcoin, Go Byte, Dash, Bitcoin Cash, Ethereum, Ethereum Classic, Zcash, Bitcoin Gold, Dogecoin and Emercoin. ivendPay terminals are designed and patented to accept payments in electronic money, cryptocurrencies and cash when connecting the corresponding cash terminal. Payment for the purchase takes a few seconds, the choice of the payment currency occurs at the time of placing the order on the screen, the payment is made by QR-code through the cryptocurrency wallet on the smartphone.
The interest in equipping vending machines with ivendPay terminals has already been shown by the companies of Malaysia and Israel, where first test networks would be installed. ivendPay compiles a waiting list for vending networks interested in buying terminals and searches for an investor to launch industrial production. According to Sergey Danilov, the universal payment terminal ivendPay for the vending machine will cost about $500. The founder of ivendPay has welcomed the appearance of Groestlcoin among integrated cryptocurrencies, as it is another step towards the realization of the basic idea of digital money - free and cross-border access to goods and services for everybody.

Introduction

As always, the past 3 months since 22nd June have been crazy busy. The bears might still be around, but the show must go on and of course has not slowed the Groestlcoin development team in the slightest. Here’s a quick overview of what has already happened since the last release: - Integrated into the bitbns exchange, with the ability to buy Groestlcoin directly with the Indian Rupee. - Groestlcoin Rebrand Vote – Whilst there was much talk and push for a rebrand vote, the overall result was almost unanimously in favour of keeping our unique and conversation-starting name. With just 83 votes to Rebrand, and 2577 votes to No Rebrand. Thank you for all who voted, the funds raised are being used to fund ongoing hosting and development costs. - Integrated into the Cryptobridge exchange. Cryptobridge is a popular decentralised exchange where you always hold the private keys to your funds, only YOU have access to them. - Groestlcoin has been added to SimpleSwap – Groestlcoin can now be swapped with over 100 other cryptocurrencies, without signing up! - Groestlcoin has been added to UnoDax, one of the leading cryptocurrency exchanges in India, with TUSD, BTC and INR trading pairs. - Groestlcoin has been added to SwapLab.cc, where you can buy Groestlcoin using Bitcoin and over 50 other altcoins. Purchasing with VISA/Mastercard is coming VERY SOON. Discussed later: - Groestlcoin has been listed on #3 largest exchange in the world on volume, Huobi Global! More on this to come further on in the announcements. - Groestlcoin has been added to the Guarda Multi-Currency Wallet. - Groestlcoin has been added to Melis Multi-Device, Multi-Account, Multi-Platform, Multi-Signature advanced wallet! Already this list is far more than most other cryptocurrencies have achieved in the past 3 months. But this is just the tip of the iceberg of what has been developed.

What's been Happening?

GRSPay Released

We are so excited for this, that it has it's own separate reddit thread. Head over there now at https://www.reddit.com/groestlcoin/comments/9ikr5m/groestlcoin_releases_grspay/? to see more on this!
https://www.melis.io/assets/logo-navbar-4b6f0d372f15b2446d3fa4c68f346e4fb08ee113941186cee58fd6135f3f8b7d.svg

Melis Wallet

The the most advanced wallet for Bitcoin, Bitcoin Cash, Litecoin and now Groestlcoin.

With Melis you have the complete control of your bitcoins and private keys, you can define spending limits policies and make use of two or more factors authentication. Melis is open source, published on GitHub.

How Melis Works?

You can create as many accounts as you want. An account is a part of your wallet that can be customised to your requirements. You can choose how many co-signers are required to spend funds. The accounts are completely independent and act like separate wallets from each other but can be accessed via the same details. A core feature of Melis is the ability to set a ‘primary’ device. With this you can set an account as ‘Secure’ so it is only viewable (and accessible at all) from the Primary device. You can have a savings account hidden from the outside world whilst also having your ‘spending’ funds available on the go. With Melis you can create a multi-signature account between N people, where up to N signatures are required to sign a transaction, choosing if any of those should be mandatory.

Core Features:

• Multi-Device – Ability to hide accounts from all but the primary account.
• Multi-Account – Multiple, entirely separate accounts in one wallet.
• Multi-Platform – Available on iOS, Android, Web, Windows, Linux and Mac OS
• Multi-Signature – Create multi-signature accounts between many people, where a certain amount of people’s signatures is required to sign a transaction. Some can be required before a transaction is signed.
• Native support for many currencies – Multiple currencies are supported, accessed all from the same wallet and backup keywords.
• Advanced Coin Control (Choose which UTXO are involved in the transaction), multiple destinations and manual fee settings.
• 2FA support for enhanced security, also available via Telegram.
• Wrong-Currency detection. The server knows if someone sends BTC to a BCH address and visa versa and automatically creates a new account to be able to recover the funds.
• A single backup using standard BIP39 mnemonics is valid and enough for an unlimited number of transactions, address and different account types

https://guarda.co/assets/images/1PGo4ID.svg?1537791124643

Guarda Wallet

Safer than ever! Desktop Light Wallet - Anonymous and fast!

With Guarda Multi-currency Desktop Light Wallet you don’t need to register. Guarda has no access to your private keys or funds. You can receive, send, store, buy and exchange cryptocurrencies in complete anonymity and safety. All these features are available on Linux, Windows or MacOS. Choose the one that suits you!
More info about Guarda wallet on www.guarda.co
https://holytransaction.com/images/logo.png

Integrated into HolyTransaction

What is HolyTransaction?

HolyTransaction gives users access to the crypto world with a universal cryptocurrency wallet and instant exchange.

Features

• Cryptocurrency Exchange HolyTransaction features a cryptocurrency exchange where you can exchange between all popular currencies with just a few clicks. Instant send from one currency to another.
• Simple to use - With a simple, no-handdles GUI, anyone can now use and have access to cryptocurrency.
• Cutting-Edge security - Following industry-best standards, and guarentee that your money is safe. Utilising hot and cold storage wallets.
• Features an API whereby you can integrate cryptocurrency support into any website, from invoice processing to white-labelled multi-currency wallets.

For more information, visit Holy Transaction here.
https://www.groestlcoin.org/wp-content/uploads/2018/09/next-grs-groestlcoin.jpg

Integrated into NEXT Wallet

What is NEXT?

NEXT is a modern, next-generation stylish open-source Desktop wallet.

Features

• Cross-Platform, NEXT runs on Windows, Linux and MacOS
• Fast and Lightweight - NEXT is an extremely fast and light wallet
• Modern User Interface - The interface is elegant and simple to use, perfect for new to cryptocurrency and veterans alike.
• In-Wallet Proposal Tab - Proposal tab will allow users to view all proposals and/or easily create a proposal.

For more information, visit NextWallet here.
https://blockchainfinancial.com/mediaserve2018/09/admin-06143647-bcf_logo_vec_256x256.png

Integrated into Blockchain Financial

What is Blockchain Financial?

Blockchain Financial is a set of web based services for individuals and companies that want to make things happen with the Cryptocurrencies Ecosystem. - For those that don't know anything about cryptocurrencies, we offer tools that will let them receive, send and operate with an assortment of coins. - For those that are already riding the wave, we offer tools that will let them do all those things that they weren't able to do.

Blockchain Financials mission

We're not here to reinvent the wheel. We're here to make it run smoother for you, and we provide some of the most useful services you'll find on the internet, made in a way that is easy to understand and use on a daily basis. In short, we're a bunch of people that claim to be Crypto Evangelists. We strongly believe in cryptocurrencies, and our main promise is to push them up so more people get involved and take all the advantages they offer.

More information from Blockchain Financial

Back in 2014, the world was taken by storm when Facebook approved the first cryptocurrencies tipping apps. The first was for Dogecoin, and the second was for multiple coins.
The project was hosted on whitepuma.net, and persisted for almost two years, built up a massive user community and gave a home to Bitcoin, Litecoin, Dogecoin and dozens of other bitcoin-based altcoins.
After very active months, the tipping hype started to fade away. Then, the developers decided to jump into the next stage: bringing not only tipping, but also mining and a widget that could be embedded on websites to allow everyone to accept payments. Sadly, the work was never completed because the project started to require an unsustainable amount of resources. Then, in a painful decision, a shutdown was announced by December 2015.
A couple of months after whitepuma.net was closed, the source code was released by its creator as Open Source on GitHub. But it wasn't maintained.
Now, some of the original members of the dev and admin teams gathered up with a handful of the WhitePuma's elite users, and decided to make something good with the best pieces of the old source code. That, with fresh new ideas and the power of the BardCanvas engine, synthesized the core of Blockchain Financial.

More info about Blockchain Financial wallet on .
For more information, visit [Blockchain Financial](www.blockchainfinancial.com)
https://www.huobi.com/image/logo.aeb4723.svg

Groestlcoin Listed on Huobi

Who are Huobi?

Huobi was founded in China and is now based in Singapore, with offices in Hong Kong, South Korea, Japan and the North America, currently sitting #3 in volume on Coinmarketcap. Huobi is a great leap forward for our growing presence in Asia and we are very excited to be listed here!
You can find the official Huobi announcement here.

Groestlcoin Core v2.16.3 - Please Update ASAP

A new major Groestlcoin Core version 2.16.3 is now available for download which includes both a Denial of Service component and a critical inflation vulnerability, so it is recommended to upgrade to it if you are running a full Groestlcoin node or a local Groestlcoin Core wallet.
v2.16.3 is now the official release version of Groestlcoin Core. This is a new major version release with a very important security updates. It is recommended to upgrade to this version as soon as possible. Please stop running versions of Groestlcoin Core affected by CVE-2018-17144 ASAP: These are 2.13.3 and 2.16.0.
As a result in this, all exchanges and services have been asked to upgrade to this version, so please be patient if wallets go in to maintenance mode on these services.

What's new in version v2.16.3?

This is a major release of Groestlcoin Core fixing a Denial of Service component and a critical inflation vulnerability (https://nvd.nist.gov/vuln/detail/CVE-2018-17144) exploitable by miners that has been discovered in Groestlcoin Core version 2.13.3 and 2.16.0. It is recommended to upgrade to 2.16.3 as soon as possible. If you only occasionally run Groestlcoin Core, then it's not necessary to run out and upgrade it right this second. However, you should upgrade it before you next run it. If you know anyone who is running an older version, tell them to upgrade it ASAP. Stored funds are not at risk, and never were at risk. At this time we believe over half of the Groestlcoin hashrate has upgraded to patched nodes. We are unaware of any attempts to exploit this vulnerability. However, it still remains critical that affected users upgrade and apply the latest patches to ensure no possibility of large reorganizations, mining of invalid blocks, or acceptance of invalid transactions occurs.

The Technicals

In Groestlcoin Core 2.13.3, an optimization was added (Bitcoin Core PR #9049) which avoided a costly check during initial pre-relay block validation that multiple inputs within a single transaction did not spend the same input twice which was added in 2012 (Bitcoin Core PR #443). While the UTXO-updating logic has sufficient knowledge to check that such a condition is not violated in 2.13.3 it only did so in a sanity check assertion and not with full error handling (it did, however, fully handle this case twice in prior to 2.1.0.6). Thus, in Groestlcoin Core 2.13.3, any attempts to double-spend a transaction output within a single transaction inside of a block will result in an assertion failure and a crash, as was originally reported. In Groestlcoin Core 2.16.0, as a part of a larger redesign to simplify unspent transaction output tracking and correct a resource exhaustion attack the assertion was changed subtly. Instead of asserting that the output being marked spent was previously unspent, it only asserts that it exists. Thus, in Groestlcoin Core 2.16.0, any attempts to double-spend a transaction output within a single transaction inside of a block where the output being spent was created in the same block, the same assertion failure will occur. However, if the output being double-spent was created in a previous block, an entry will still remain in the CCoin map with the DIRTY flag set and having been marked as spent, resulting in no such assertion. This could allow a miner to inflate the supply of Groestlcoin as they would be then able to claim the value being spent twice.
Groestlcoin would like to publicly thank Reddit user u/Awemany for finding CVE-2018-17144 and reporting it (https://lists.linuxfoundation.org/pipermail/bitcoin-core-dev/2018-Septembe000064.html). You deserve gratitude and appreciation from cryptoworld, and you have ours. If you want to support him for his work, please consider donating to him on his bitcoin cash address: bitcoincash:qr5yuq3q40u7mxwqz6xvamkfj8tg45wyus7fhqzug5
http://i.imgur.com/3YhyNZK.png

Groestlcoin Electrum-GRS 3.2.2 - Ledger & Trezor Edition

What is Electrum-GRS?

Electrum-GRS is a lightweight "thin client" groestlcoin wallet Windows, MacOS and Linux based on a client-server protocol. Its main advantages over the original Groestlcoin client include support for multi-signature wallets and not requiring the download of the entire block chain.

Changes:

• Qt GUI: seed word auto-complete during restore
• performance improvements (wallet, and Qt GUI)
• hardware wallets: show debug message during device scan
• add regtest support (via --regtest flag)
• other minor bugfixes and usability improvements
• If present, libsecp256k1 is used to speed up elliptic curve operations. The library is bundled in the Windows, MacOS, and Android binaries. On Linux, it needs to be installed separately.
• Transactions that are dropped from the mempool are kept in the wallet as 'local', and can be rebroadcast. Previously these transactions were deleted from the wallet.
• The scriptSig and witness part of transaction inputs are no longer parsed, unless actually needed. The wallet will no longer display 'from' addresses corresponding to transaction inputs, except for its own inputs.
• The partial transaction format has been incompatibly changed. This was needed as for partial transactions the scriptSig/witness has to be parsed, but for signed transactions we did not want to do the parsing. Users should make sure that all instances of Electrum-GRS they use to co-sign or offline sign, are updated together.
• Signing of partial transactions created with online imported addresses wallets now supports significantly more setups. Previously only online p2pkh address + offline WIF was supported. Now the following setups are all supported: > online {p2pkh, p2wpkh-p2sh, p2wpkh} address + offline WIF, > online {p2pkh, p2wpkh-p2sh, p2wpkh} address + offline seed/xprv, > online {p2sh, p2wsh-p2sh, p2wsh}-multisig address + offline seeds/xprvs > (Potentially distributed among several different machines) Note that for the online address + offline HD secret case, you need the offline wallet to recognize the address (i.e. within gap limit). Having an xpub on the online machine is still the recommended setup, as this allows the online machine to generate new addresses on demand.
• Segwit multisig for bip39 and hardware wallets is now enabled (both p2wsh-p2sh and native p2wsh).
• Ledger: offline signing for segwit inputs (#3302) This has already worked for Trezor. Offline segwit signing can be combined with online imported addresses wallets.
• Added Revealer plugin. ( https://revealer.cc ) Revealer is a seed phrase back-up solution. It allows you to create a cold, analog, multi-factor backup of your wallet seeds, or of any arbitrary secret. The Revealer utilizes a transparent plastic visual one time pad.
• Fractional fee rates: the Qt GUI now displays fee rates with 0.1 gro/byte precision, and also allows this same resolution in the Send tab.
• Hardware wallets: a "show address" button is now displayed in the Receive tab of the Qt GUI. (#4316)
• Trezor One: implemented advanced/matrix recovery (#4329)
• Windows: use dnspython to resolve dns instead of socket.getaddrinfo (#4422)
• Importing minikeys: use uncompressed pubkey instead of compressed (#4384)
• SPV proofs: check inner nodes not to be valid transactions (#4436)
• Qt GUI: there is now an optional "dark" theme (#4461)
• Several other minor bugfixes and usability improvements.
• Fix DNS resolution on Windows
• Fix websocket bug in daemon

http://i.imgur.com/3YhyNZK.png

Electrum-GRS Mobile Android

What is Electrum-GRS Mobile?

Electrum-grs is a lightweight "thin client" groestlcoin wallet Android based on a client-server protocol. Its main advantages over the original Groestlcoin client include support for multi-signature wallets and not requiring the download of the entire block chain.

Changes

• Android: fix some crashes
• If present, libsecp256k1 is used to speed up elliptic curve operations. The library is bundled in the Windows, MacOS, and Android binaries. On Linux, it needs to be installed separately.
• Two-factor authentication is available on Android. Note that this will only provide additional security if one time passwords are generated on a separate device.
• Semi-automated crash reporting is implemented for Android.
• Qt/Kivy: added "gro" as optional base unit.
• Kivy GUI: significant performance improvements when displaying history and address list of large wallets; and transaction dialog of large transactions.

Groestlcoin EasyVanity Released

Groestlcoin EasyVanity is a Windows app is built from the ground-up in C# and makes it easier than ever before to create your very own bespoke Groestlcoin address(es), even whilst not connected to the internet! You can even generate multiple keys with the same prefix and leave it on overnight whilst your CPU or GPU collects and stores these addresses locally.

If you're tired of the random, cryptic addresses generated by regular groestlcoin clients, then Groestlcoin EasyVanity is the right choice for you to create a more personalized address.

Features

• Ability to continue finding keys after first one is found • Includes warning on startup if connected to the internet • Ability to output keys to a text file (And shows button to open that directory) • Ability to make your match case sensitive (Where possible) • Show and hide the private key with a simple toggle switch, and copy the private key straight to your clipboard • Show full output of commands • Includes statistics whilst the application is running • Ability to choose between Processor (CPU) and Graphics Card (GPU) • Automatically detects 32 or 64 bit systems • Features both a Light and Dark Material Design inspired Themes • EasyVanity's search is probabilistic, and the amount of time required to find a given pattern depends on how complex the pattern is, the speed of your computer, and whether you get lucky. • EasyVanity includes components to perform address searching on your CPU (vanitygen) and your OpenCL-compatible GPU (oclvanitygen). Both can be built from source, and both are included in the Windows binary package. • Prefixes are exact strings that must appear at the beginning of the address. When searching for prefixes, Easyvanity will ensure that the prefix is possible, and will provide a difficulty estimate. • The percentage displayed just shows how probable it is that a match would be found in the session so far. If it finds your address with 5% on the display, you are extremely lucky. If it finds your address with 92% on the display, you are unlucky. If you stop EasyVanity with 90% on the display, restart it, and it finds your address with 2% on the display, your first session was unlucky, but your second session was lucky. • EasyVanity uses the OpenSSL random number generator. This is the same RNG used by groestlcoin and a good number of HTTPS servers. It is regarded as well-scrutinized. Guessing the private key of an address found by EasyVanity will be no easier than guessing a private key created by groestlcoin itself. • To speed up address generation, EasyVanity uses the RNG to choose a private key, and literally increments the private key in a loop searching for a match. As long as the starting point is not disclosed, if a match is found, the private key will not be any easier to guess than if every private key tested were taken from the RNG. EasyVanity will also reload the private key from the RNG after 10,000,000 unsuccessful searches (100M for oclvanitygen), or when a match is found and multiple patterns are being searched for. • Free software - MIT. Anyone can audit the code. • Written in C# - The code is short, and easy to review.

Groestlcoin Sentinel (Android & Blackberry) – Mainnet + Testnet

What is Sentinel?

Groestlcoin Sentinel is the easiest and fastest way to track/receive/watch payments in your offline Groestlcoin Wallets. Groestlcoin Sentinel is compatible with any standard Groestlcoin address, BIP44 XPUB (Extended Public Key) BIP49 YPUB and BIP84 ZPUB
Groestlcoin Sentinel is a great solution for anyone who wants the convenience and utility of a hot wallet for receiving payments directly into their cold storage (or hardware wallets). Sentinel accepts XPUB's, YPUB'S, ZPUB's and individual Groestlcoin address. Once added you will be able to view balances, view transactions, and (in the case of XPUB's, YPUB's and ZPUB's) deterministically generate addresses for that particular wallet.

What's New?

• Track Segwit BIP84 ZPUBs extended pubkeys
• Sweep Segwit BIP49 (P2SH-P2WPHK) and Segwit BIP84 (bech32) amounts into selected account/address
• Broadcast hex tx
• Added option to chose from Binance and Upbit as selected Exchange
• Added Korean Won as price option
• Receive address closes upon receipt of groestlcoin
• Fix EUR price  ### Groestlcoin P2SH Paper Wallet #### What is Groestlcoin P2SH Paper Wallet? Groestlcoin P2SH paperwallet is a simple groestlcoin paper wallet generator that utilizes Segregated Witness (SegWit) Pay To Witness Public Key Hash (P2WPKH) addresses and transactions.

The P2SH paperwallet supports creating P2SH paperwallets in bulk, keypair generation with QR codes and sweeping tool. Groestlcoin believes strongly in privacy, the live version does not collect and store IP or transaction data.

Changes

• Details section to validate private keys and to view corresponding segwit address, public key and redeem script.
• Segwit brain wallet
• Removed Vanity generator as it was very slow. (Please use VanityGen command line or EasyVanity instead)
• Rebranded segwit paperwallet to p2sh paperwallet
• Favicon updated
• Testnet support added
• Groestlcoin Sentinel can sweep funds from private keys and QR codes generated with this tool
• Groestlcoin Sentinel Testnet can sweep funds from private keys and QR codes generated with this tool
• Electrum-GRS can import private keys using the console and the importprivkey() command. Import as P2SH segwit: importprivkey('p2wpkh-p2sh:KzTLBvC6mNudLBjEmwYCuk3jrZ7sZS8CzFDzcrwnDM2CVpH8vNAn')
• Electrum-GRS Testnet can import private keys using the console and the importprivkey() command. Import as P2SH segwit: importprivkey('p2wpkh-p2sh:cNNDi1AT8XNng2wJ5HNFN41toufU9XZ2bW8MGi7c9SGw4hnMuASk')

Features

• Keypair generation with QR Codes
• Bulk address generator
• Key Sweeping Tool to move all funds belonging to a single SegWit private key.  ### Groestlcoin BECH32 Paper Wallet Released #### What is Groestlcoin BECH32 Paper Wallet? Groestlcoin BECH32 paperwallet is a simple groestlcoin paper wallet generator that utilizes Segregated Witness (SegWit) Pay To Witness Public Key Hash (P2WPKH) addresses and transactions.

The BECH32 paperwallet supports creating BECH32 paperwallets in bulk, keypair generation with QR codes and sweeping tool. Groestlcoin believes strongly in privacy, the live version does not collect and store IP or transaction data.

Features

• Detail section to validate private keys and to view corresponding segwit address, public key and redeem script.
• Segwit brain wallet
• Testnet support
• Groestlcoin Sentinel can sweep funds from private keys and QR codes generated with this tool
• Groestlcoin Sentinel Testnet can sweep funds from private keys and QR codes generated with this tool
• Electrum-GRS can import private keys using the console and the importprivkey() command. Import as P2SH segwit: importprivkey('p2wpkh-p2sh:KzTLBvC6mNudLBjEmwYCuk3jrZ7sZS8CzFDzcrwnDM2CVpH8vNAn')
• Electrum-GRS Testnet can import private keys using the console and the importprivkey() command. Import as P2SH segwit: importprivkey('p2wpkh-p2sh:cNNDi1AT8XNng2wJ5HNFN41toufU9XZ2bW8MGi7c9SGw4hnMuASk')
• Bulk address generator
• Key Sweeping Tool to move all funds belonging to a single SegWit private key.


Groestlcoin Web Wallet Update 1.4

What is Groestlcoin Web Wallet?

Groestlcoin Webwallet is an open source, multisignature, HD Wallet and more! Webwallet is a a open source browser based Groestlcoin webwallet.
Webwallet is a playground for Groestlcoin in javascript to experiment with. It supports multisig, OP_HODL, RBF and many more. Groestlcoin believes strongly in privacy, the live version does not collect and store IP or transaction data.

Changes:

• RBF (Replace-By-Fee) enabled by default
• Bech32 address support added
• Testnet support added

https://iancoleman.github.io/bip39/
I hope I’m wrong here as I’ve already created a fair few wallets with this glorious site.
Stay with me, as I’m breaking this down so you can tear me a new one if I’ve misunderstood something…
All this is being done manually following the BIP39 specs
Let’s start with a set of hex values to get us a 128-bit entropy to start…
9b 19 3b 32 17 eb 5b 6f 0d 18 8a 92 5d 44 1e 93
This gives us the below raw binary value… 10011011000110010011101100110010000101111110101101011011011011110000110100011000100010101001001001011101010001000001111010010011
To get us the 132 bits needed for the 12 word mnemonic, we need to add the 4-bit checksum to the end. This is done by taking the first 4 bits from the SHA256 hash of the raw binary and adding it to the end…
Hash in hex: EECD064AC143BD279FA3D6F5ED4E4FA9E1D67D87D56B1D9CBA40AC5FB620F968 First 4 bits = “E” = 1110
Raw binary + Checksum gives us the 132 bits. This is split into 11-bit chunks, to give us the 12 binary values needed for the words. (remember to minus 1 from the numbered lines here as the list actually starts at 0 (zero).

• 10011011000 - 1240 - only
• 11001001110 - 1614 - six
• 11001100100 - 1636 - smart
• 00101111110 - 382 - cool
• 10110101101 - 1453 - remember
• 10110111100 - 1468 - resource
• 00110100011 - 419 - crucial
• 00010001010 - 138 - bacon
• 10010010010 - 1170 - myself
• 11101010001 - 1873 - tuition
• 00000111101 - 61 - amateur
• 00100111110 - 318 - chief

All seems straight forward, right?
If you put the above hex value into the website, everything above is correct except for the final word. The website assigns a checksum of 1001 to the raw binary/entropy, making the final value 00100111001 (313, cheese).
Has there been an oversight of the website or (and more likely the issue) am I misunderstanding the checksum generation? My method results in an “invalid mnemonic” when I put in my manual mnemonic.
Edit: Formatting.

forkdrop.io and follow us on Twitter https://twitter.com/forkdrop
We are at 65 Bitcoin Forks/Airdrops 13 Altcoin, 12 Historic and 59 exchanges tracked.
This week, we launched our Guides section which features includes a multi-part in-depth guide for using the bitcoin_fork_claimer tool securely and privately on an Ubuntu live-boot system. They include many screenshots to help step through the process at a comfortable pace.
https://forkdrop.io/novices-guide-to-claiming-forked-bitcoin-value.html
Among other things, we take you through setting up a live-boot Linux environment:
https://forkdrop.io/secure-live-boot-ubuntu-for-bitcoin-keys.html
Installing and running the Tor Browser in said environment:
https://forkdrop.io/running-tor-browser-from-ubuntu-live-boot.html
Downloading Ian Coleman's BIP39 tool for running offline and using it:
https://forkdrop.io/running-bip-39-tool-on-secure-offline-ubuntu-system.html https://forkdrop.io/using-ian-colemans-bip-39-tool.html
Covering the basics of u/ymgve's tool for preparing to run it:
https://forkdrop.io/preparing-to-use-bitcoin-fork-claimer-tool.html https://forkdrop.io/finding-parameters-for-bitcoin-fork-claimer-tool.html
Tips on finding exchanges to deposit while keeping your identity as private as you want to be:
https://forkdrop.io/scouting-exchanges-to-sell-forked-bitcoin-value.html
And then actually running the scripts:
https://forkdrop.io/running-bitcoin-fork-claimer-on-ubuntu.html
20 articles in total which will grow in size as we go forward.
There were also some minor feature improvements this week, such as adding the marker icon to the per-coin and per-exchange pages.
Summary of dataset updates:

• Added note for United Bitcoin (UBTC) transactions taking a while due to miner's transaction selection oddities.
• Added full details for ClassicBitcoin (CBTC) which was formerly tracked as Bitcoin Classic (BCL). Coin is forking April 1st, @ 516095, 1:1 ratio. Also has a small registered airdrop program for 10,000 coins
• Hpx exchange does require providing some identity for withdrawal (no picture ID, just name country and ID card numbers), so we downgraded it from no KYC to ambiguous state.
• EtherZero (ETZ) is now depositable and tradable on Exrates
• Lightning Bitcoin (LBTC) network shut down due to technical issues, Was promised to be back online on the 28th, but no word as of yet.
• Added Graviex exchange for opening Bitcoin Cash Plus (BCP). KYC not required for withdrawal
• Added warning that Bitcon Cash Plus (BCP) does not have replay protection between BCH and BCP
• Added price feed info for Ontology (ONT) (Neo fork) from coinmarketcap.com
• Added Coin2Coin exchange, which trades claims for ONT, ETC, SBTC, ETF, and BCD. None are depositable. KYC required
• Binance takes deposits and trades Ontology (ONT)
• Gate.io takes deposits and trades Ontology (ONT)
• Huobi.pro takes deposits and trades Ontology (ONT), also added trading of claims (no deposit) for Bitcoin File (BIFI)
• OKEx trades claims for Ontolgoy (ONT), but not depositable
• Added Bitbns exchange which takes deposits and trades Ontology (ONT). Indian government ID required for KYC.
• Litecoin Private (LTCP) depositable and tradeable on Octaex
• New fork: Bitcoin Transfer (BTCT) - looks abandoned
• New fork: Bitcoin Master (BCM) - recently announced, details very sparse
• New fork: BitcoinZeroX (BTCZ) - Hybrid airdrop comparable to BTCP, not happening for another couple months
• New fork: Bitcoin Coral (BTCO) - a bit old, looks abandoned
• Marked Gate.io as now requires KYC for withdrawal, also downgraded it in our rankings :(
• New fork: Bitcoin Star (BCS) - block 503999, 1000:1 ratio

Stuff we are working on:

1. More guides/articles & improved presentation of existing articles
2. Night mode (much requested!)
3. Better price info
4. Tell us what you want to see!

Ways to support the site:

1. Participate in BitcoinAirdrops - we read it all
2. Submit us your info, corrections, etc.
3. Follow us on Twitter: https://twitter.com/forkdrop
4. Participate in the Disqus discussion forms for each coin/exchange
5. Use the referral links when signing up for exchanges <3 <3 <3
6. Send donations to donation addresses on the footer of the site

All the Best,
The Forkdrop.io Team

This is quite advanced. This guide assumes you have some basic experience with the command line, can run Linux and you understand the basics of keys/signing/broadcasting transactions. And that you can compile and run Bitcoin Core and run Electrum. Also, some JSON experience is also nice.
Move you bitcoins to safe addresses first. It is best to use a new seed. Although the procedure in this guide is safe even for hot addresses (containing bitcoins), there is always a risk of a critical mistake. So play it safe.
Why such a guide? I followed these steps because I did not want to expose the keys to any online machine at all. Even if the keys do not have any bitcoins, you can some day have bitcoins sent to these addresses or you have a fork that you have not claimed. All can be stolen if you exposed your key.
This procedure should work with everything that Electrum supports (except maybe F2A that may be not supported on the SBTC chain), so Electrum seed legacy or segwit, LedgeTrezor with legacy or segiwt-p2sh (m/'49) derivation. Similarly, any BIP39 seeds or a single key. are also fine.

1. Download Electrum. git clone https://github.com/spesmilo/electrum
2. Apply my patch patch -P0 also this article. The guide assumes that you use patched Electrum from now on.
   
3. Run the patched Electrum and catch up with your wallets you want to claim (the wallets can and rather should be watch only, or on ledgetrezor, otherwise your keys are exposed). Now go offline or set localhost as your server that Electrum connects to so no connection is performed. It's required so Electrum will not update the wallet after you edit it.
   
4. You can manually create a transaction from the command line but you can use Electrum GUI. You need to locate the wallet file and remove all the transactions from the wallet file except for the one that funds the address you want to claim (the wallet obviously must not be encrypted but for watch-only this is OK). This is tricky. You need to make sure, you gave a proper JSON file, so all the final commas must be dropped. So "addr_history":, "transactions": , "tx_fees":, "txi", "txo", and "verified_tx3": should only contain the funding transaction(s), i.e. the one that you want to spend from.
   
5. Run Electrum and check if the wallet is OK. Electrum will show an error if not. You will probably make a few errors so go back to editing the wallet.
   
6. Download SBTC bitcoin core clone. git clone https://github.com/superbitcoin/SuperBitcoin
   
7. Compile it and let it sync the blockchain (it will take a long time). Run it it with as large -dbcache= as you can. If you have a Bitcoin blockchain you can copy the blocks up to the fork date and issue sbtcd with -reindex. It will just reindex them and it will be faster.
   
8. Generate a sbtc address with sbtc-cli getnewaddress. You can skip this step and send directly to an exchange but this intermediate step is safer.
   
9. Create a transaction in Electrum to this address. Select all the bitcoins and use as small fee as possible (SBTC blocks are empty so any fee above 1 SBTCsat/byte should be OK).
   
10. Save the transaction to a pendrive
    
11. Download and install Kubuntu 16.04 (Kubuntu has all the QT libraries for Electrum) on a pen drive.
    
12. Copy patched Electrum and the save the transaction to a pen drive (separate from Kubuntu will be more convenient).
    
13. Run Kubuntu from the USB without any network access. Run Electrum from the pendrive. Create a wallet from the seed or private keys. The wallets are stored in RAM so after you reboot the computer, they will be gone. Load the transaction, sign it and save it to the pen drive.
    
14. Go back to the SBTC Core on the online machine. Display the raw transaction (starts with the hex=). Check in the SBTC Core if it is correct sbtc-cli decoderawtransaction hex
    
15. If it looks fine (and your blockchain got synced), broadcast it sbtc-cli sendrawtransaction hex
    

If there is no error, congratulations, you sent the transaction to the specified address. If it is to your SBTC Core wallet, wait until it confirms and send it further with sbtc-cli setfee feeperkb sbtc-cli sendtoaddress "addr" value "" "" true true
I'm going to update this guide when I figure out the BCD transactions intrinsics. You can download and run the BitcoinDiamond Core clone in the meantime.
SBTC tips: 1KjuY8CTrwMhdLt3uF3hCcSgfkHMyo1ELf

TLDR; The site that has been running nice and quietly on TOR for 18 months. We thought today is a good day to make the url public outside of our group of amigos.
PGP: 3DB6 FF02 6EBA 6AFF 63AF 2B6E DCE5 3FA2 EC58 63D8 Bitcoin: 18FNZPvYeWUNLmnS6bQyJSVXYPJ87cssMM TOR: http://xvultx4llltx7w2d.onion

Vultronix encrypted social network.

Abstract: Since time began, social interaction has always been private to those within the same vicinity. Today, however, much data is sent encrypted to a third party, gets decrypted on arrival and then stored among mountains of un-encrypted data, stored for financial gain creating giant honeypots. These giant honeypots of un-encrypted data are just too irresistible to those who have the power to request access.
We propose a solution to these centralized honeypots by enforcing client side encryption in such a way that the server has no access to the encrypted content, we believe this can be achieved via a mix of key hashing, PGP, AES and Onion routing. We acknowledge the current JavaScript anonymity problem and see a future where secure hardware will encrypt/decrypt the data for the user. We propose the below as a simple POC for inspiration of future development, open for all to copy, enhance and most importantly, to scrutinize.
1. What is the example? A truly client side TOR based encrypted centralized social network. Allowing users to interact anonymously online without the ability of the host to spy on the user. Trust with the host is established via signed open source Javascript. Everything is delivered directly from the host via TOR without any use of CDNs.
2. Centralized over decentralized? The greatest problem available to implementing encryption to the masses is user experience. We developed Vultronix to allow the user to interact with others securely via a familiar feeling platform. More experienced users can download the code and setup their own .onion domain, further removing the risk of a centralized authority.
3. Registration The user is required to fill in 3 fields. For familiarity we've named them the following - Email address, Password and Words list. The user is not required to enter their actual email but is encouraged to generate a string with a lot of entropy; it is acknowledged that the less experienced user will probably make up an email address, both the password and words field should be as random as possible. The entropy of these 3 fields is on what the user's encryption depends.
Note: as the system is not decentralized, the logins are only available to brute force attack by the host or if/when the database is compromised and dumped online. To achieve the best security a password tool should be used with 3 very random strings. A more user friendly solution is to make up a very random but easy to remember email address via a random mnemonic seed generator similar to BIP39, a difficult password the user can remember and a short word list.
Given a user selects the following log in details which, let's assume, were created by a BIP39 generator. + email: [email protected] + password: liquid sketch husband + Word list: shove proof dismiss gauge
The above contains 12 completely random words.
The browser will concatenate these to [email protected] sketch husbandshove proof dismiss gauge This value would then be hashed, creating the following hash. 90bc6ba57145e2116ea10d136ec49061e9a15c5694b171ba1e5753ab02e141e4
This hash is hashed forward 5001 times, on the 2000th hash the sha-256 becomes a sha-512 hash in the following fashion. SHA512(2000th hash + 2000th hash) and is stored momentarily as the "loginHash" variable. The loop continues on with all further loops taking a different path that can't be reached by hashing forward the login hash. The 3000th hash is saved as the "passphrase" variable The 4000th hash is saved as the "encryptionKey" variable and the 5001st hash ends up being Hashed again for good measure. loginHash = SHA512(loginHash + 5001st hash);
At the same time during registration the user's browser will generate a 4096 PGP key pair. The PGP password is the "passphrase" variable. Both the passphrase and the encryptionKey never reach the server. The PGP pub/priv keys are both AES encrypted with the encryptionKey as the password and sent to the server.
Note: The PGP public key is never sent to the server unencrypted as we don't want someone with access to the Database to be able to analyze who is friends with who.
Also generated at sign up is a UUID, this is AES encrypted as well.
Sent to the server on sign up is the following. + encrypted: PGP public key - AES encrypted string. + encrypted: PGP private key - AES encrypted string. + encrypted: UUID - AES encrypted string + loginHash: SHA-512 hash.
Upon signing in, the user fills out his profile. This data (including any images uploaded) is encrypted client side by the user, the user encrypts a copy to himself using his own PGP public key, which is currently decrypted in his browser session, then encrypts this again with his AES encryption key.
4. Login A user will login with the same credentials used at sign up, the loginHash will reach the server and the server will find a match and send back the user's encrypted credentials. The user's client will decrypt these with his "passphrase" and "encryptionKey", neither of which have ever been sent to the server.
Note: If a MITM intercepts a user loginHash over the wire, the MITM will be able to retrieve the encrypted data from the server, but will never be able to decrypt it, and won't have any further access to the user's data.
Once the user decrypts his credentials data, he'll have access to his UUID, the client will then request from the server an encrypted friends list object, the client will decrypt this and populate client side his friends list. This will contain the public PGP key of each of his friends along with a friendship key unique to each friendship as well as a generated shared password unique to each friendship. The client will also send requests to the server to look for feed updates, inbox messages, new friend requests and accepted friend requests etc.
5. Friend requests To keep friendships private, a user must send another user a friend request token. Since everything in the Database is encrypted , it isn't possible for a user to simply look up a friend. Via the friend request page the user will fill out a short message and press a button. The user is presented with a SHA-256 hash that will expire after 2 weeks. The user simply needs to pass this hash onto his friend via other means of contact, the friend then enters the hash into the friend request page, the friend will then see a thumbnail of the user (or whatever logo the user has chosen for his profile picture) followed by the short message the receiving friend should recognise, e.g. "Hey Alice it's Bob, please accept my friend request", Alice accepts the friend request and they're now friends, Alice won't have access to Bob's profile page until Bob next logs in.
Behind the scenes, the following happens: Bob's message is concatenated to a generated UUID This string is hashed many times like the loginHash An object is created containing Bob's following encrypted data: + PGP Pub Key + friendshipUUID unique to this friendship + sendersFriendshipUUID + acceptersFriendshipUUID + Bob's Name + Bob's thumbnail (all images are converted to base64 strings in the browser then encrypted/decrypted client side) + Request message etc.
This encrypted data is sent to the server, the friendship token is equivalent to the final login hash that a user generates on login. Bob doesn't, however, send Alice this final hashed token, he sends her an earlier version of a hash. Alice will enter this hash, her browser will roll it forward creating the decryption key and eventually the friendship token that resides on the server, her client will send this to the server, the server will respond with the encrypted data. Only she can decrypt the data as only she has the earlier hash of the friend request token.
She decrypts Bob's friendship data, adds it to her FriendsList data, encrypts the latest copy and sends it through to the server for safe keeping. Alice's client will now create an encrypted accepted friendrequest object submitting it to the server. Alice will then use Bob's PGP key and their new friendship password they share to double encrypt her profile to Bob.
When Bob logs in next (or if currently online via web sockets) he will receive the accepted friendrequest token. Bob's client will then do what Alice's did and update his friends list etc and send a copy of his profile through to Alice. Bob and Alice will now see each other's new status updates, album updates etc.
Note: A new friend can never see old status updates, this should be considered a feature.
6. Chat and instant messages Users can see when other users are online and chat via web sockets, they can also send offline messages via their inbox. These messages are double encrypted. If Bob sends Alice a message, the following happens: Bob's client will encrypt the message using Alice's PGP public key and a copy using his own PGP public key, he'll then encrypt both using their shared friendship password and place 2 entries into the database. If Alice is online the server will push up her messages instantly via web sockets, if not, she'll see the message the next time she logs in, she'll notice this as the inbox icon will be red to signify unread messages.
Note: If a user has Vultronix open in another tab, he'll hear a sound when a new message is received as well as a keyboard sound when his friend is typing.
7. Group invites Groups allow shared users to associate online in private without having any access to who other members of the group are, users can also send private encrypted messages to other users of a group in full privacy. Anyone can create a group. On group creation the group's admin client will generate a random password, the admin can give the group a logo and message etc. The admin can then create a group invite token and the recipient of the token can sign up to the group in the same way that a user would accept/decline a friendship request. Once a user is a member of a group, he too can invite friends. All of these people will share an AES encryption key which they'll get via decryption of the encrypted invite request. Each user will be able to download a shared membership list of the group, which will not be able to identify any users. This list will contain user PGP keys that are used when a member sends another member of the group a private 1 - 1 message.
TLDR; Everyone in the group can start threads, comment in threads, invite new friends etc, no one outside of the group will even know of the group's existence, the group's description, name, members list etc. All of it is encrypted and private. No member will know that other members have privately messaged each other. No member will be able to find another member's profile. However, if they wish to be friends, they can private message a friendship request token. Members can have their own groups and private message friend request tokens through to members to join other private groups.
8. Status updates When a user creates a new status message, the user's friends will see the message appear in their feed either in real time if they're online, or the next time they login. When a user fills in the status box, the user can optionally add a photo or youtube video link (caution: external services could be used to track you) and then press save. After the user saves the status the following happens:
The status is encrypted and saved to the server. To reduce client computation time as well as server storage, only one copy of the status is saved to the server. The client will encrypt and upload a new encrypted message for each of his friends, this message will simply hold a AES decryption key and a status ID, the friend's client will then request this status and decrypt it. All of the user's friends can comment on the status, only the user will be able to click through to their profiles. It's impossible for user's friends to be able to interact with each other outside of their shared friend's status comment box.
9. Shops Private encrypted shops would be easily implemented via the following: The shop owner would setup shops in a similar way to setting up a group, inviting customers to his private shop with tokens. He could send these tokens to his friends in his friends list or new people he meets in a private members group via private message. This would allow the shop owner to sell to only people he trusts, e.g. his grandmother or aunt etc. The shop owner would have complete privacy. The shop owner would keep control of all his bitcoin private keys. He would enter a list of bitcoin addresses, then add items to his shop. Upon adding an item, the client would submit an encrypted copy of the item to the server for each customer of his store. Customers would browse his store and see an item, the item would have a bitcoin address to pay to. The customer would enter a message, be it his email address for a digital order or a postal address for a physical order. He would then pay to the bitcoin address and hit submit. The shop owner would see a page with orders and see the email address and manually check the bitcoin address has funds.
This would allow sellers and buyers online to have great protection, providing they're buying/selling from people they trust. If the server is hacked and database stolen, no one will have access to any bitcoin as no private keys would ever be on the server and everything is encrypted, so no one would know what shops even exist, unless they have a personal invite to that store.
This kind of private store could be very useful for people living under oppressive regimes. If, for example, someone wants to learn about Capitalism and would like to buy Capitalist literature but they live in a censored Communist state, they could access via TOR and order anonymously without ever having to worry about the site being hacked and their government going through the data and heavily punishing them, possibly with death. They would be at risk though of the literature being confiscated in the mail so they'd be better off to order a digital copy and have it emailed or, perhaps, the seller could simply copy and paste the text into a private message to the seller.
The possibilities would be endless for the above, we have not implemented this though as we're not sure of the legality. If someone decided to sell something illegal and law enforcement wanted information on the buyeseller, we would never be able to retrieve it from the database. If, however, they managed to become a member of a store, they could perhaps tell us a UUID that might represent the store and we could delete the shop at their request, but not much else. For this reason we're not going down this path, it is however fascinating to think of.
We'd predict that OpenBazaar would one day offer the ability of hidden stores, not just the ability to route via TOR. For any OB users we've added a OpenBazaar field to the member profile info page.
The goal of this project is to show that client side end to end encryption is possible for intermediate users and not that difficult to implement. We hope this inspires people to build something similar and better or, perhaps, fork the code and fix some bugs etc.
We appreciate your time, if you enjoyed this or atleast appreciate our effort, our bitcoin address is below. Bitcoin: 18FNZPvYeWUNLmnS6bQyJSVXYPJ87cssMM
PS: The code will be uploaded to a public Github profile this week.
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