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Messages - gruve_p

#16


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.



If you are an ordinary user of Groestlcoin and simply want the convenience of a web wallet with the security of a real application and support for multi-signature, then Elecrum-GRS is the right choice for you.

Changelog Electrum-GRS 3.2.3:
• hardware wallet: the Safe-T mini from Archos is now supported.
• BIP39 seeds: if a seed extension (aka passphrase) contained multiple consecutive whitespaces or leading/trailing whitespaces then the derived addresses were not following spec. This has been fixed, and affected should move their coins. The wizard will show a warning in this case.
• Revealer: the PRNG used has been changed (#4649)
• fix Linux distributables: 'typing' was not bundled, needed for python 3.4
• fix #4626: fix spending from segwit multisig wallets involving a Trezor cosigner when using a custom derivation path
• Several other minor bugfixes and usability improvements.

Changelog Electrum-GRS 3.2.2:
• 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

Changelog Electrum-GRS 3.1.2:
• Capital gains: For each outgoing transaction, the difference between the acquisition and liquidation prices of outgoing coins is displayed in the wallet history. By default, historical exchange rates are used to compute acquisition and liquidation prices. These values can also be entered manually, in order to match the actual price realized by the user. The order of liquidation of coins is the natural order defined by the blockchain; this results in capital gain values that are invariant to changes in the set of addresses that are in the wallet. Any other ordering strategy (such as FIFO, LIFO) would result in capital gain values that depend on the presence of other addresses in the wallet.
• Local transactions: Transactions can be saved in the wallet without being broadcast. The inputs of local transactions are considered as spent, and their change outputs can be re-used in subsequent transactions. This can be combined with cold storage, in order to create several transactions before broadcasting them. Outgoing
transactions that have been removed from the memory pool are also saved in the wallet, and can be broadcast again.
• Checkpoints: The initial download of a headers file was replaced with hardcoded checkpoints. The wallet uses one checkpoint per retargeting period. The headers for a retargeting period are downloaded only if transactions need to be verified in this period.
• The 'privacy' and 'priority' coin selection policies have been merged into one. Previously, the 'privacy' policy has been unusable because it was was not prioritizing confirmed coins. The new policy is similar to 'privacy', except that it de-prioritizes addresses that have unconfirmed coins.
• The 'Send' tab of the Qt GUI displays how transaction fees are computed from transaction size.
• The wallet history can be filtered by time interval.
• Replace-by-fee is enabled by default. Note that this might cause some issues with wallets that do not display RBF transactions until they are confirmed.
• Watching-only wallets and hardware wallets can be encrypted.
• The SSL checkbox option was removed from the GUI.
• The Trezor One and T hardware wallet is now supported.
• The Ledger hardware wallet is now supported.
• BIP84: native segwit p2wpkh scripts for bip39 seeds and hardware wallets can now be created when specifying a BIP84 derivation path. This is usable with Trezor and Ledger.
• Windows: the binaries now include ZBar, and QR code scanning should work.
• The Wallet Import Format (WIF) for private keys that was extended in 3.0 is changed. Keys in the previous format can be imported, compatibility is maintained. Newly exported keys will be serialized as "script_type:original_wif_format_key".
• BIP32 master keys for testnet once again have different version bytes than on mainnet. For the mainnet prefixes {x,y,Y,z,Z}|{pub,prv}, the corresponding testnet prefixes are {t,u,U,v,V}|{pub,prv}. Note that due to this change, testnet wallet files created with previous versions of Electrum must be considered broken, and they need to be recreated from seed words.
• A new version of the Electrum-GRS protocol is required by the client (version 1.2). Servers using older versions of the protocol will not be displayed in the GUI.

Changelog Electrum-GRS 3.0.6:
• Moved away from Linux binary file. Users must compile from source now.
• Moved away from electrum-grs-server codebase to electrumx-grs 1.2
• The source code is relicensed under the MIT Licence
• Separation between plugins and GUIs
• The command line uses jsonrpc to communicate with the daemon
• New command: 'notify <address> <url>'
• Alternative coin selection policy, designed to help preserve user privacy. Enable it by setting the Coin Selection preference to Privacy.
• The install wizard has been rewritten and improved
• Support minikeys for private key import and sweeping
• QT: add colors to labels
• The wallet file format has been upgraded. This upgrade is not backward compatible, which means that a wallet upgraded to the 2.7 format will not be readable by earlier versions of Electrum-GRS. Multiple accounts inside the same wallet are not supported in the new format; the Qt GUI will propose to split any wallet that has several accounts. Make sure that you have saved your seed phrase before you upgrade Electrum-GRS.
• This version introduces a separation between wallets types and keystores types. 'Wallet type' defines the type of Groestlcoin contract used in the wallet, while 'keystore type' refers to the method used to store private keys.
• Replace-By-Fee: RBF transactions are supported in Qt. A warning is displayed in the history for transactions that are replaceable, have unconfirmed parents, or that have very low fees.
• Qt GUI:
   - A fee slider is visible in the in send tab
   - The Address tab is hidden by default, can be shown with Ctrl-A
   - UTXOs are displayed in the Address tab
• Seed phrases can be extended with a user-chosen passphrase. The length of seed phrases is standardized to 12 words, using 132 bits of entropy. In the wizard, the type of the seed is displayed in the seed input dialog.
• Add number of confirmations to request status.
• In the GUI, refer to passphrase as 'seed extension'.
• Wizard: Hide seed options in a popup dialog.
• Separate sign and broadcast buttons in Qt tx dialog
• Allow spaces in private keys
• Add size to transaction details window
• Move plot plugin to main code
• Merge exchange_rate plugin with main code
• Faster synchronization and transaction creation
• Use fee slider for static fees
• Add fee slider to RBF dialog
• Simplify fee preferences.
• Add Testnet support
• Allow daemon to be launched in the foreground
• Qt: use separate tabs for addresses and UTXOs
• Qt: update fee slider with a network callback
• Enforce https on exchange rate APIs
• Use hardcoded list of exchanges
• Move 'Freeze' menu to Coins (utxo) tab
• Wallet file encryption using ECIES: A keypair is derived from the wallet password. Once the wallet is decrypted, only the public key is retained in memory, in order to save the encrypted file.
• The daemon requires wallets to be explicitly loaded before commands can use them. Wallets can be loaded using: 'electrum-grs daemon load_wallet [-w path]'. This command will require a password if the wallet is encrypted.
• Invoices and contacts are stored in the wallet file and are no longer shared between wallets. Previously created invoices and contacts files may be imported from the menu.
• Fees improvements:
    - Child Pays For Parent (CPFP) dialog in the GUI.
    - RBF is automatically proposed for low fee transactions.
• The GUI shows a blue icon when connected using a proxy.
• Show paid invoices in history tab
• Improve CPFP dialog
• Multiple Chain Validation: Electrum-GRS will download and validate block headers sent by servers that may follow different branches of a fork in the Groestlcoin blockchain. Instead of a linear sequence,block headers are organized in a tree structure. Branching points are located efficiently using binary search. The purpose of MCV is to detect and handle blockchain forks that are invisible to the classical SPV model.
• The desired branch of a blockchain fork can be selected using the network dialog. Branches are identified by the hash and height of the diverging block. Coin splitting is possible using RBF transaction
• MultiGroestl, Groestlwallet, Simple Groestlcoin support: If the user enters a BIP39 seed, the full derivation path is configurable in the install wizard.
• Option to send only confirmed coins
• Qt GUI:
    - Network dialog uses tabs and gets updated by network events.
    - The gui tabs use icons
• Daemon: The wallet password can be passed as parameter to the JSONRPC API.
• Validate contacts on import
• Command-line option for locktime
• Force headers download if headers file is corrupted
• Add websocket to windows builds
• The project was migrated to Python3 and Qt5. Python2 is no longer supported. If you cloned the source repository, you will need to run "python3 setup.py install" in order to install the new dependencies.
• Segwit support:
    - Native segwit scripts are supported using a new type of seed. The version number for segwit seeds is 0x100. The install wizard will not create segwit seeds by default; users must opt-in with the segwit option.
    - Native segwit scripts are represented using bech32 addresses, following BIP173. Please note that BIP173 is still in draft status, and that other wallets/websites may not support it. Thus, you should keep a non-segwit wallet in order to be able to receive groestlcoins during the transition period. If BIP173 ends up being rejected or substantially modified, your wallet may have to be restored from seed. This will not affect funds sent to bech32 addresses, and it will not affect the capacity of Electrum-GRS to spend these funds.
    - The BIP32 master keys of segwit wallets are serialized using new version numbers. The new version numbers encode the script type, and they result in the following prefixes:
         * xpub/xprv : p2pkh or p2sh
         * ypub/yprv : p2wpkh-in-p2sh
         * Ypub/Yprv : p2wsh-in-p2sh
         * zpub/zprv : p2wpkh
         * Zpub/Zprv : p2wsh
These values are identical for mainnet and testnet; tpub/tprv prefixes are no longer used in testnet wallets.
    - The Wallet Import Format (WIF) is similarly extended for segwit scripts. After a base58-encoded key is decoded to binary, its first byte encodes the script type:
         * 128 + 0: p2pkh
         * 128 + 1: p2wpkh
         * 128 + 2: p2wpkh-in-p2sh
         * 128 + 5: p2sh
         * 128 + 6: p2wsh
         * 128 + 7: p2wsh-in-p2sh
The distinction between p2sh and p2pkh in private key means that it is not possible to import a p2sh private key and associate it to a p2pkh address.
• A new version of the Electrum-GRS protocol is required by the client (version 1.1). Servers using older versions of the protocol will not be displayed in the GUI.
• By default, transactions are time-locked to the height of the current block. Other values of locktime may be passed using the command line.
• Sweeping minikeys: search for both compressed and uncompressed pubkeys
• Qt GUI: sweeping now uses the Send tab, allowing fees to be set
• Windows: if using the installer binary, there is now a separate shortcut for "Electrum-GRS Testnet"
• OS notifications for incoming transactions
• Better transaction size estimation:
    - fees for segwit txns were somewhat underestimated
    - some multisig txns were underestimated
    - handle uncompressed pubkeys
• The JSONRPC interface is password protected
• JSONRPC commands are disabled if the GUI is running, except 'ping', which is used to determine if a GUI is already running

Changelog Electrum-GRS 2.5.4:
• Linux binary file included
• Fixed sweeping private keys
• Fixed signing/verifying messages
• Electrum-GRS servers updated to 2.5.4
• Installwizard: do not allow direct copy-paste of the seed
• The QT GUI supports multiple windows in the same process. When a new Electrum-GRS instance is started, it checks for an already running Electrum-GRS process, and connects to it.
• The network layer uses select(), so all server communication is handled by a single thread. Moreover, the synchronizer, verifier, and exchange rate plugin now run as separate jobs within the networking thread instead of as their own threads.
• Plugins are revamped
• Simplified Chinese wordlist
• Dynamic Fees: using estimatefee value returned by server
• Various GUI improvements
• Arbitrary m-of-n multisig wallets are supported (n<=15).
• Transaction fees set manually in the GUI are retained, including when the user uses the '!' shortcut.
• New 'email' plugin, that enables sending and receiving payment requests by email.
• improvements to the transaction dialog:
    - request password after showing transaction
    - show change addresses in yellow color
• Improved logic for the network layer.
• More efficient coin selection. Spend oldest coins first, and minimize the number of transaction inputs.
• The command line accepts the '!' syntax to send the maximum amount available. It can be combined with the '--from' option. Example: 'payto <destination> ! --from <from_address>'
• The command line also accepts a '?' shortcut for private keys arguments, that triggers a prompt.
• Payment requests can be signed with a SSL certificate, and published as bip70 files in a public web directory.
• Show amounts (thousands separators and decimal point) according to locale in GUI
• Show unmatured coins in balance
• Faster startup, thanks to the following optimizations:
   1. Transaction input/outputs are cached in the wallet file
   2. Fast X509 certificate parser, not using pyasn1 anymore.
• The 'Invoices' and 'Send' tabs have been merged.
• Contacts are stored in a separate file, shared between wallets.
• A Search Box is available in the GUI (Ctrl-S)
• Own addresses are shown in green in the Transaction dialog.
• Address History dialog.
• The password dialog will ask for password again if the user enters a wrong password
• The Master Public Key dialog displays which keys belong to the wallet, and which are cosigners
• The transaction dialog will ask to save unsaved transaction received from cosigner pool, when user clicks on 'Close'
• The multisig restore dialog accepts xprv keys.

Features
• Encrypted wallet - the file that contains your groestlcoins is protected with a password. You are protected from thieves.
• Deterministic key generation - If you lose your wallet, you can recover it from its seed. You are protected from your own mistakes.
• Instant on - the client does not download the blockchain, it requests that information from a server. No delays, always up-to-date.
• Freedom and Privacy - The server does not store user accounts. You are not tied to a particular server, and the server does not need to know you.
• No scripts - Electrum-GRS does not download any script. A compromised server cannot send you arbitrary code and steal your groestlcoins.
• No single point of failure - The server code is open source, anyone can run a server.
• Transactions are signed locally - Your private keys are not shared with the server. You do not have to trust the server with your money.
• Firewall friendly - The client does not need to open a port, it simply polls the server for updates.
• Free software - Gnu GPL v3. Anyone can audit the code.
• Written in Python - The code is short, and easy to review.
• User Friendly - Support for Groestlcoin URIs, signed URIs and Groestlcoin aliases
• No Lock-In - You can export your private keys and use them in other groestlcoin clients.
• No Downtimes - Electrum-GRS servers are decentralized and redundant. Your wallet is never down.
• Proof Checking - Electrum-GRS Wallet verifies all the transactions in your history using SPV.
• Cold Storage - Keep your private keys offline, and go online with a watching-only wallet. Sign transactions from a computer taht is always offline. Broadcast them from a machine that does not have your keys.
• Multisign - Split the permission to spend your coins between several wallets using parallel BIP32 derivations and P2SH addresses ("2 of 2", "2 of 3"). Compact serialization format for unsigned or partially signed transactions, that includes the BIP32 master public key and derivation needed to sign inputs. Serialized transactions can be sent to cosigners or to cold storage using QR codes
• Cosigner Pool plugin - encrypted communication channel for multisign wallets, to send and receive partially signed transactions.
• Get noticed - Run a public Electrum-GRS server, publish your message and reach thousands of Groestlcoin users

It is appreciated if feedback of the following is provided:
1. Can you receive coins with legacy addresses? (small amounts to avoid losing them)
2. Can you receive coins with bech32 addresses? (small amounts to avoid losing them)
3. Can you receive coins with legacy testnet addresses? (small amounts to avoid losing them)
4. Can you receive coins with bech32 testnet addresses? (small amounts to avoid losing them)
5. Can you send coins with legacy addresses? (small amounts to avoid losing them)?
6. Can you send coins with bech32 addresses? (small amounts to avoid losing them)?
7. Can you send coins with legacy testnet addresses? (small amounts to avoid losing them)?
8. Can you send coins with bech32 testnet addresses? (small amounts to avoid losing them)?
9. Does the cosigner pool work when using a multi-signature wallet?
10. Does the virtual keyboard work when it asks to enter your wallet password?
11. Does it automatically detect servers under Tools - Network?
12. Are you able to sweep private keys?
13. Are you able to sign/verify messages?
14. Are you able to encrypt/decrypt messages?

This application is licensed under the GPL version 3. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1. PM me
2. Email: [email protected]
3. Post reports of erros in this topic.

Important:
Store your secret phrase somewhere safe!
The multi-signature and non native segwit addresses starts with a "3" and not with a "F".
Electrum-GRS creates an encrypted filename default_wallet instead of wallet.dat (like in Groestlcoin Core)
• Location Windows: Navigate to C:\Users\USER NAME\AppData\Roaming\Electrum-grs\wallets (or open windows explorer and enter %appdata%\Electrum-grs\wallets) and back up your default_wallet file by making a copy of it and moving it to a secure location.
• Location Mac: Navigate to ~/Library/Application Support/Electrum-grs/wallets and back up your default_wallet file by making a copy of it and moving it to a secure location.

You can download it using the links below and be up and running with Groestlcoin in 5 minutes.

Download the OSX wallet here: https://github.com/Groestlcoin/electrum-grs/releases/download/v3.2.3/electrum-grs-3.2.3.dmg
Note: The QR code scanner is not supported in OSX binary

Download Windows installer here: https://github.com/Groestlcoin/electrum-grs/releases/download/v3.2.3/electrum-grs-3.2.3-setup.exe
Download Windows standalone wallet here: https://github.com/Groestlcoin/electrum-grs/releases/download/v3.2.3/electrum-grs-3.2.3.exe
Download Windows portable version here: https://github.com/Groestlcoin/electrum-grs/releases/download/v3.2.3/electrum-grs-3.2.3-portable.exe
                                       

Linux wallet instructions:
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

Source code:
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
Github Source Icons: https://github.com/Groestlcoin/electrum-grs-icons
Github Source locale: https://github.com/Groestlcoin/electrum-grs-locale
#17


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 build your own services with it.

Features
• Support to broadcast transactions online. Broadcast a raw transaction in hex format over the Groestlcoin network.
• Multiple platforms - Supports all browsers
• API - Complete REST and Websocket API for quering blocks, transactions, addresses and receiving live updates
• Light - Thin data model using groestlcoind RPC interfase to validate blockchain information. Fast groestlcoind blockchain syncronization (~1hrs for the entire livenet), using RocksDB for data storage and, optionally, raw groestlcoind data files processing.
• Exhaustive - Reports on double spend attempts, outpoints confirmations, outputs spend status reports. Input and Outputs hyperlinks in transactions. Extended view in transactions to show advance details.
• Open source - Opensourced, written in go.

It is appreciated if feedback of the following is provided:
1. Can you broadcast a raw transaction?

Blockbook is licensed under GPLv3. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to blockbook, no compensation will be given. Use blockbook solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1. PM me
2. Email: [email protected]
3. Post reports of erros in this topic.

Blockbook is available via https://blockbook.groestlcoin.org/

Source code: https://github.com/Groestlcoin/blockbook
#18


Blockbook testnet is an open-source Groestlcoin testnet 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 testnet RPC.



Blockbook Testnet REST API provides you with a convenient, powerful and simple way to read data from the groestlcoin testnet network and build your own services with it.

Features
• Support to broadcast transactions online. Broadcast a raw transaction in hex format over the Groestlcoin testnet network.
• Multiple platforms - Supports all browsers
• API - Complete REST and Websocket API for quering blocks, transactions, addresses and receiving live updates
• Light - Thin data model using groestlcoind RPC interfase to validate blockchain information. Fast groestlcoind blockchain syncronization (~1hrs for the entire livenet), using RocksDB for data storage and, optionally, raw groestlcoind data files processing.
• Exhaustive - Reports on double spend attempts, outpoints confirmations, outputs spend status reports. Input and Outputs hyperlinks in transactions. Extended view in transactions to show advance details.
• Open source - Opensourced, written in go.

It is appreciated if feedback of the following is provided:
1. Can you broadcast a raw transaction?

Blockbook testnet is licensed under GPLv3. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to blockbook testnet, no compensation will be given. Use blockbook testnet solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1. PM me
2. Email: [email protected]
3. Post reports of erros in this topic.

Blockbook testnet is available via https://blockbook-test.groestlcoin.org/

Source code: https://github.com/Groestlcoin/blockbook
#19
Important Announcements / Groestlcoin ASIC Statement
October 31, 2018, 06:55:33 PM
We would like to make a formal statement to address the release of the new Baikal BK-G28 ASIC which supports our Groestl algorithm. Many of you have had questions and discussions regarding whether Groestlcoin will or should hard-fork to a new Proof-of-Work algorithm.

A testament to Groestlcoins recent success
ASICs are largely considered the devil for altcoins and altcoin mining, and with good reason. As a community and as the Groestlcoin team, we would love for the security of Groestlcoin to increase whilst remaining a GPU-only coin. Unfortunately, as the coin becomes more successful, people will ultimately create ASICs for any algorithm that is profitable, and the production of ASICs are a testament to the booming success Groestlcoin has been over the past year. The time has come to look at how these ASICs affect Groestlcoin as a community and as a cryptocurrency.

Initially, it makes sense for the developers to change the PoW algorithm to keep mining decentralised. ASICs threaten the original goal of Groestlcoin and it threatens the mining profitability of GPU miners. We are aware that a small majority of the Groestlcoin community vote for changing the PoW algorithm whenever there is a poll or discussion on the matter. This statement will try to explain as best we can the effects of a hard-fork of this nature and the constant struggle that would follow.

Are you hard-forking?
Ever since the genesis block of Groestlcoin over 4 years ago, it has faced these hard-fork dilemmas. At first, it was purely a CPU-only minable coin, a month later, it was made possible for GPUs to mine Groestlcoin. Around a year ago, open source implementations of FPGAs started popping up on Github. Now Groestlcoin faces its first ASIC. At each stage, the consideration to hard-fork to another algorithm was discussed and at each time to this pointit was agreed that no hard-fork was necessary. Based on these decisions over the past 4+ years,Groestlcoin is still standing and has seen vast growths in community and development.

With the revelation of ASICs for Groestlcoin, the discussion was met again with all the developers and after heated discussions, the unanimous consensus amongst the team is to not hard-fork away from ASIC miners. Given the recent 51% and double-spend attacks performed on several big-named altcoins over the past two years, our personal views on ASICs have changed dramatically. We now undoubtedly believe that; for the reasons we hope to express in this statement, ASICs are the correct and inevitable evolution for any successful cryptocurrency.

Why has this decision been made?
We do not feel that any PoW algorithm in existence today can be considered GPU-Only, if there aren't ASICs for an algorithm, chances are there will be, and we can guarantee there are FPGAs in production that are far out-weighing the profitability and usefulness of GPUs.The issues behind running from an ASIC each time it is found after each algorithm change are as follows:

· Make no mistake, hard-forks are messy and can be disastrous if not handled with finesse. With each algorithm change requires a hard-fork, and with each hard-fork splits the coin into two chains and all nodes (users, exchanges, pool operators etc.) must then move to the new chain. It can be considerable work for node operators to update the nodes/wallets to continue operating.
Hard-forking due to major bugs in the code is obviously necessary, however, it is far more difficult to convince node operators to keep operating the new chain if just for an algorithm change. With a relatively small cryptocurrency, this proves difficult, and if two chains were to split and consensus fails, the fungibility of Groestlcoin could be destroyed — You can imagine the issues that come from a split chain, consider a merchant is accepting Groestlcoin but is still on the old chain, and you send Groestlcoin from the new chain. That merchant would not receive the payment. Also consider if Exchange 1 moved to the new chain but Exchange 2 did not, and you tried withdrawing your funds between exchanges.

· After the algorithm change, our hash rate will inevitably decline. With a smaller hash-rate and lower difficulty, the blockchain is more vulnerable to attack via 51% attacks and double-spend attacks. Pool operators may stop supporting Groestlcoin or take time to support the new algorithm and miners will find new coins to mine.

· Mining with a GPU is not more decentralised. There are people running over a thousand GPUs mining farms currently doing the same as what ASICs will do, but at a higher monetary environmental cost.

Finality, Security, and Risks
It is the duty of the developers of a decentralised currency to ensure that the network is secure and functions the way it was intended to function. For Groestlcoin to succeed as a currency we need transaction finality i.e. once a transaction is confirmed, the users want to know that nobody can take this money away from us — This is what we are trying to move away with a cryptocurrency as opposed to a traditional FIAT banking system, aren't we? Proof-of-Work provides that, the history of the chain must not be altered without doing a lot of work. With Groestlcoin, we know that the only way we can lose that money is if an alternate history appears that doesn't include our payment, and that alternate history has more work than the history we see.

The facts remain that GPU-mineable coins are far more prone to being attacked than coins with ASICs and ultimately the security of the blockchain must be the core priority of the Groestlcoin core developers in order to protect the community's funds from future potential attacks. If nobody mines Groestlcoin, the coin dies, if the coin is 51% attacked, the image of the coin is dramatically damaged as well as potentially people's funds and can lead to delisting's or permanently high confirmation requirements. The purpose of Proof-of-Work is to make attacking as expensive as possible, and ASICs help to achieve this.

We have already touched upon some of the issues that come with low-hash-rate PoW cryptocurrencies, but we'd like to take a moment to explain further the risks of GPU-Only mining. Many of you would have seen of the issues other cryptocurrencies have faced in the past year with regards to 51% and double spend attacks and the damage that they have done to the image of the coins. As we mentioned above, having an ASIC developed shows that Groestlcoin has been successful thus far, and now Groestlcoin can be protected by hardware from these catastrophic attacks. The value of a cryptocurrency can only truly be quantified by how secure the network of that cryptocurrency is.

With more security comes with it the reduced risk of 51% attacks where a single centralised entity can change the history of the blockchain, or exclusively mine all empty blocks and claim the block rewards for themselves — Grinding transactions to a halt and effectively killing the chain. Additionally, an attacker would be able to double-spend coins which we'll not go into detail but has been discussed in great depth elsewhere. For coins with ASICs, the incentives to protect the network against this manipulation protect against this type of user manipulation, due to the costs associated with ASICs.

The decentralisation gained with a fairly distributed hash-rate of GPU-miners is overshadowed by the fact the currency is considerably more vulnerable to 51% attacks by centralised parties.We hope you'll agree that the advantage that ASIC-mining have in the longer term over GPU-mining are plentiful.

So... Embracing ASICs
With all things considered, we believe embracing ASICs is more viable than trying to fight them off to the detriment of the coins security and the risks that come with that. However, we do not believe that any cryptocurrency should embrace an abusive ASIC monopoly. ASIC manufacturers have a vested interest to protect the network from attack in order to protect their long-term investment of the manufacturing and maintaining of their developed hardware. We feel we should all accept ASICs as a sign of coin maturity.

For those community members screaming that ASICs are a disaster, please know that ASICs will not kill Groestlcoin. ASICs were first seen on Bitcoin and Litecoin, and they have helped secure the growing network from attacks ever since. Many other non-dominant coins were forced to merge-mine with Bitcoin and Litecoin in order to remain secure from attacks. Groestlcoin is the most dominant cryptocurrency using the Groestl512 PoW algorithm. Due to this; if we forked from this algorithm, another 'less dominant' cryptocurrency using Groestl would receive this security and become more secure than Groestlcoin — Effectively conceding its place as a dominant blockchain and a dominant cryptocurrency in the mining space.

In Closing...
In summary, the decision to not hard-fork to a new algorithm at this time has not been made lightly. We hope that you recognise the indirect benefits outweigh the smaller but more visible detriments of ASICs running on our network. Ultimately, we feel there is a greater chance of the coin dying from chasing an ASIC-Resistant PoW algorithm than from the introduction of ASICs on to our network.As the core developers, we MUST consider the coin security above all else.

We recognise that ASICs are not an ideal solution for a globally recognised decentralised cryptocurrency. We feel that neither are GPU-Only mining; currently the security offered from GPU-Only mining is not secure enough to be considered a safe, globally recognised currency. We feel that sacrificing the increased network security and risking chain forks back to another imperfect solution is not the right answer. This doesn't mean we will never fork away from ASICs, but we need a suitable solution that both ensures the security of the network and ensures the network is suitably more decentralised.

What's next for Groestlcoin?
From Groestlcoin inception until now, the coin's development never stopped, and will never stop no matter what challenges we might face in the future.

We will continue to work hard so we can give to our community the best tech there is for Peer-to-Peer Electronic Cash System.

Below you'll find our next developments and here you can see all our development progress: https://www.groestlcoin.org/development-progress/.
#20


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.



If you are an ordinary user of Groestlcoin and simply want the convenience of a web wallet with the security of a real application and support for multi-signature, then Elecrum-GRS is the right choice for you.

Changelog Electrum-GRS 3.2.2:
• 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

Changelog Electrum-GRS 3.1.2:
• Capital gains: For each outgoing transaction, the difference between the acquisition and liquidation prices of outgoing coins is displayed in the wallet history. By default, historical exchange rates are used to compute acquisition and liquidation prices. These values can also be entered manually, in order to match the actual price realized by the user. The order of liquidation of coins is the natural order defined by the blockchain; this results in capital gain values that are invariant to changes in the set of addresses that are in the wallet. Any other ordering strategy (such as FIFO, LIFO) would result in capital gain values that depend on the presence of other addresses in the wallet.
• Local transactions: Transactions can be saved in the wallet without being broadcast. The inputs of local transactions are considered as spent, and their change outputs can be re-used in subsequent transactions. This can be combined with cold storage, in order to create several transactions before broadcasting them. Outgoing
transactions that have been removed from the memory pool are also saved in the wallet, and can be broadcast again.
• Checkpoints: The initial download of a headers file was replaced with hardcoded checkpoints. The wallet uses one checkpoint per retargeting period. The headers for a retargeting period are downloaded only if transactions need to be verified in this period.
• The 'privacy' and 'priority' coin selection policies have been merged into one. Previously, the 'privacy' policy has been unusable because it was was not prioritizing confirmed coins. The new policy is similar to 'privacy', except that it de-prioritizes addresses that have unconfirmed coins.
• The 'Send' tab of the Qt GUI displays how transaction fees are computed from transaction size.
• The wallet history can be filtered by time interval.
• Replace-by-fee is enabled by default. Note that this might cause some issues with wallets that do not display RBF transactions until they are confirmed.
• Watching-only wallets and hardware wallets can be encrypted.
• The SSL checkbox option was removed from the GUI.
• The Trezor One and T hardware wallet is now supported.
• The Ledger hardware wallet is now supported.
• BIP84: native segwit p2wpkh scripts for bip39 seeds and hardware wallets can now be created when specifying a BIP84 derivation path. This is usable with Trezor and Ledger.
• Windows: the binaries now include ZBar, and QR code scanning should work.
• The Wallet Import Format (WIF) for private keys that was extended in 3.0 is changed. Keys in the previous format can be imported, compatibility is maintained. Newly exported keys will be serialized as "script_type:original_wif_format_key".
• BIP32 master keys for testnet once again have different version bytes than on mainnet. For the mainnet prefixes {x,y,Y,z,Z}|{pub,prv}, the corresponding testnet prefixes are {t,u,U,v,V}|{pub,prv}. Note that due to this change, testnet wallet files created with previous versions of Electrum must be considered broken, and they need to be recreated from seed words.
• A new version of the Electrum-GRS protocol is required by the client (version 1.2). Servers using older versions of the protocol will not be displayed in the GUI.

Changelog Electrum-GRS 3.0.6:
• Moved away from Linux binary file. Users must compile from source now.
• Moved away from electrum-grs-server codebase to electrumx-grs 1.2
• The source code is relicensed under the MIT Licence
• Separation between plugins and GUIs
• The command line uses jsonrpc to communicate with the daemon
• New command: 'notify <address> <url>'
• Alternative coin selection policy, designed to help preserve user privacy. Enable it by setting the Coin Selection preference to Privacy.
• The install wizard has been rewritten and improved
• Support minikeys for private key import and sweeping
• QT: add colors to labels
• The wallet file format has been upgraded. This upgrade is not backward compatible, which means that a wallet upgraded to the 2.7 format will not be readable by earlier versions of Electrum-GRS. Multiple accounts inside the same wallet are not supported in the new format; the Qt GUI will propose to split any wallet that has several accounts. Make sure that you have saved your seed phrase before you upgrade Electrum-GRS.
• This version introduces a separation between wallets types and keystores types. 'Wallet type' defines the type of Groestlcoin contract used in the wallet, while 'keystore type' refers to the method used to store private keys.
• Replace-By-Fee: RBF transactions are supported in Qt. A warning is displayed in the history for transactions that are replaceable, have unconfirmed parents, or that have very low fees.
• Qt GUI:
   - A fee slider is visible in the in send tab
   - The Address tab is hidden by default, can be shown with Ctrl-A
   - UTXOs are displayed in the Address tab
• Seed phrases can be extended with a user-chosen passphrase. The length of seed phrases is standardized to 12 words, using 132 bits of entropy. In the wizard, the type of the seed is displayed in the seed input dialog.
• Add number of confirmations to request status.
• In the GUI, refer to passphrase as 'seed extension'.
• Wizard: Hide seed options in a popup dialog.
• Separate sign and broadcast buttons in Qt tx dialog
• Allow spaces in private keys
• Add size to transaction details window
• Move plot plugin to main code
• Merge exchange_rate plugin with main code
• Faster synchronization and transaction creation
• Use fee slider for static fees
• Add fee slider to RBF dialog
• Simplify fee preferences.
• Add Testnet support
• Allow daemon to be launched in the foreground
• Qt: use separate tabs for addresses and UTXOs
• Qt: update fee slider with a network callback
• Enforce https on exchange rate APIs
• Use hardcoded list of exchanges
• Move 'Freeze' menu to Coins (utxo) tab
• Wallet file encryption using ECIES: A keypair is derived from the wallet password. Once the wallet is decrypted, only the public key is retained in memory, in order to save the encrypted file.
• The daemon requires wallets to be explicitly loaded before commands can use them. Wallets can be loaded using: 'electrum-grs daemon load_wallet [-w path]'. This command will require a password if the wallet is encrypted.
• Invoices and contacts are stored in the wallet file and are no longer shared between wallets. Previously created invoices and contacts files may be imported from the menu.
• Fees improvements:
    - Child Pays For Parent (CPFP) dialog in the GUI.
    - RBF is automatically proposed for low fee transactions.
• The GUI shows a blue icon when connected using a proxy.
• Show paid invoices in history tab
• Improve CPFP dialog
• Multiple Chain Validation: Electrum-GRS will download and validate block headers sent by servers that may follow different branches of a fork in the Groestlcoin blockchain. Instead of a linear sequence,block headers are organized in a tree structure. Branching points are located efficiently using binary search. The purpose of MCV is to detect and handle blockchain forks that are invisible to the classical SPV model.
• The desired branch of a blockchain fork can be selected using the network dialog. Branches are identified by the hash and height of the diverging block. Coin splitting is possible using RBF transaction
• MultiGroestl, Groestlwallet, Simple Groestlcoin support: If the user enters a BIP39 seed, the full derivation path is configurable in the install wizard.
• Option to send only confirmed coins
• Qt GUI:
    - Network dialog uses tabs and gets updated by network events.
    - The gui tabs use icons
• Daemon: The wallet password can be passed as parameter to the JSONRPC API.
• Validate contacts on import
• Command-line option for locktime
• Force headers download if headers file is corrupted
• Add websocket to windows builds
• The project was migrated to Python3 and Qt5. Python2 is no longer supported. If you cloned the source repository, you will need to run "python3 setup.py install" in order to install the new dependencies.
• Segwit support:
    - Native segwit scripts are supported using a new type of seed. The version number for segwit seeds is 0x100. The install wizard will not create segwit seeds by default; users must opt-in with the segwit option.
    - Native segwit scripts are represented using bech32 addresses, following BIP173. Please note that BIP173 is still in draft status, and that other wallets/websites may not support it. Thus, you should keep a non-segwit wallet in order to be able to receive groestlcoins during the transition period. If BIP173 ends up being rejected or substantially modified, your wallet may have to be restored from seed. This will not affect funds sent to bech32 addresses, and it will not affect the capacity of Electrum-GRS to spend these funds.
    - The BIP32 master keys of segwit wallets are serialized using new version numbers. The new version numbers encode the script type, and they result in the following prefixes:
         * xpub/xprv : p2pkh or p2sh
         * ypub/yprv : p2wpkh-in-p2sh
         * Ypub/Yprv : p2wsh-in-p2sh
         * zpub/zprv : p2wpkh
         * Zpub/Zprv : p2wsh
These values are identical for mainnet and testnet; tpub/tprv prefixes are no longer used in testnet wallets.
    - The Wallet Import Format (WIF) is similarly extended for segwit scripts. After a base58-encoded key is decoded to binary, its first byte encodes the script type:
         * 128 + 0: p2pkh
         * 128 + 1: p2wpkh
         * 128 + 2: p2wpkh-in-p2sh
         * 128 + 5: p2sh
         * 128 + 6: p2wsh
         * 128 + 7: p2wsh-in-p2sh
The distinction between p2sh and p2pkh in private key means that it is not possible to import a p2sh private key and associate it to a p2pkh address.
• A new version of the Electrum-GRS protocol is required by the client (version 1.1). Servers using older versions of the protocol will not be displayed in the GUI.
• By default, transactions are time-locked to the height of the current block. Other values of locktime may be passed using the command line.
• Sweeping minikeys: search for both compressed and uncompressed pubkeys
• Qt GUI: sweeping now uses the Send tab, allowing fees to be set
• Windows: if using the installer binary, there is now a separate shortcut for "Electrum-GRS Testnet"
• OS notifications for incoming transactions
• Better transaction size estimation:
    - fees for segwit txns were somewhat underestimated
    - some multisig txns were underestimated
    - handle uncompressed pubkeys
• The JSONRPC interface is password protected
• JSONRPC commands are disabled if the GUI is running, except 'ping', which is used to determine if a GUI is already running

Changelog Electrum-GRS 2.5.4:
• Linux binary file included
• Fixed sweeping private keys
• Fixed signing/verifying messages
• Electrum-GRS servers updated to 2.5.4
• Installwizard: do not allow direct copy-paste of the seed
• The QT GUI supports multiple windows in the same process. When a new Electrum-GRS instance is started, it checks for an already running Electrum-GRS process, and connects to it.
• The network layer uses select(), so all server communication is handled by a single thread. Moreover, the synchronizer, verifier, and exchange rate plugin now run as separate jobs within the networking thread instead of as their own threads.
• Plugins are revamped
• Simplified Chinese wordlist
• Dynamic Fees: using estimatefee value returned by server
• Various GUI improvements
• Arbitrary m-of-n multisig wallets are supported (n<=15).
• Transaction fees set manually in the GUI are retained, including when the user uses the '!' shortcut.
• New 'email' plugin, that enables sending and receiving payment requests by email.
• improvements to the transaction dialog:
    - request password after showing transaction
    - show change addresses in yellow color
• Improved logic for the network layer.
• More efficient coin selection. Spend oldest coins first, and minimize the number of transaction inputs.
• The command line accepts the '!' syntax to send the maximum amount available. It can be combined with the '--from' option. Example: 'payto <destination> ! --from <from_address>'
• The command line also accepts a '?' shortcut for private keys arguments, that triggers a prompt.
• Payment requests can be signed with a SSL certificate, and published as bip70 files in a public web directory.
• Show amounts (thousands separators and decimal point) according to locale in GUI
• Show unmatured coins in balance
• Faster startup, thanks to the following optimizations:
   1. Transaction input/outputs are cached in the wallet file
   2. Fast X509 certificate parser, not using pyasn1 anymore.
• The 'Invoices' and 'Send' tabs have been merged.
• Contacts are stored in a separate file, shared between wallets.
• A Search Box is available in the GUI (Ctrl-S)
• Own addresses are shown in green in the Transaction dialog.
• Address History dialog.
• The password dialog will ask for password again if the user enters a wrong password
• The Master Public Key dialog displays which keys belong to the wallet, and which are cosigners
• The transaction dialog will ask to save unsaved transaction received from cosigner pool, when user clicks on 'Close'
• The multisig restore dialog accepts xprv keys.

Features
• Encrypted wallet - the file that contains your groestlcoins is protected with a password. You are protected from thieves.
• Deterministic key generation - If you lose your wallet, you can recover it from its seed. You are protected from your own mistakes.
• Instant on - the client does not download the blockchain, it requests that information from a server. No delays, always up-to-date.
• Freedom and Privacy - The server does not store user accounts. You are not tied to a particular server, and the server does not need to know you.
• No scripts - Electrum-GRS does not download any script. A compromised server cannot send you arbitrary code and steal your groestlcoins.
• No single point of failure - The server code is open source, anyone can run a server.
• Transactions are signed locally - Your private keys are not shared with the server. You do not have to trust the server with your money.
• Firewall friendly - The client does not need to open a port, it simply polls the server for updates.
• Free software - Gnu GPL v3. Anyone can audit the code.
• Written in Python - The code is short, and easy to review.
• User Friendly - Support for Groestlcoin URIs, signed URIs and Groestlcoin aliases
• No Lock-In - You can export your private keys and use them in other groestlcoin clients.
• No Downtimes - Electrum-GRS servers are decentralized and redundant. Your wallet is never down.
• Proof Checking - Electrum-GRS Wallet verifies all the transactions in your history using SPV.
• Cold Storage - Keep your private keys offline, and go online with a watching-only wallet. Sign transactions from a computer taht is always offline. Broadcast them from a machine that does not have your keys.
• Multisign - Split the permission to spend your coins between several wallets using parallel BIP32 derivations and P2SH addresses ("2 of 2", "2 of 3"). Compact serialization format for unsigned or partially signed transactions, that includes the BIP32 master public key and derivation needed to sign inputs. Serialized transactions can be sent to cosigners or to cold storage using QR codes
• Cosigner Pool plugin - encrypted communication channel for multisign wallets, to send and receive partially signed transactions.
• Get noticed - Run a public Electrum-GRS server, publish your message and reach thousands of Groestlcoin users

It is appreciated if feedback of the following is provided:
1. Can you receive coins with legacy addresses? (small amounts to avoid losing them)
2. Can you receive coins with bech32 addresses? (small amounts to avoid losing them)
3. Can you receive coins with legacy testnet addresses? (small amounts to avoid losing them)
4. Can you receive coins with bech32 testnet addresses? (small amounts to avoid losing them)
5. Can you send coins with legacy addresses? (small amounts to avoid losing them)?
6. Can you send coins with bech32 addresses? (small amounts to avoid losing them)?
7. Can you send coins with legacy testnet addresses? (small amounts to avoid losing them)?
8. Can you send coins with bech32 testnet addresses? (small amounts to avoid losing them)?
9. Does the cosigner pool work when using a multi-signature wallet?
10. Does the virtual keyboard work when it asks to enter your wallet password?
11. Does it automatically detect servers under Tools - Network?
12. Are you able to sweep private keys?
13. Are you able to sign/verify messages?
14. Are you able to encrypt/decrypt messages?

This application is licensed under the GPL version 3. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1. PM me
2. Email: [email protected]
3. Post reports of erros in this topic.

Important:
Store your secret phrase somewhere safe!
The multi-signature and non native segwit addresses starts with a "3" and not with a "F".
Electrum-GRS creates an encrypted filename default_wallet instead of wallet.dat (like in Groestlcoin Core)
• Location Windows: Navigate to C:\Users\USER NAME\AppData\Roaming\Electrum-grs\wallets (or open windows explorer and enter %appdata%\Electrum-grs\wallets) and back up your default_wallet file by making a copy of it and moving it to a secure location.
• Location Mac: Navigate to ~/Library/Application Support/Electrum-grs/wallets and back up your default_wallet file by making a copy of it and moving it to a secure location.

You can download it using the links below and be up and running with Groestlcoin in 5 minutes.

Download the OSX wallet here: https://github.com/Groestlcoin/electrum-grs/releases/download/v3.2.2/electrum-grs-v3.2.2.dmg
Note: The QR code scanner is not supported in OSX binary

Download Windows installer here: https://github.com/Groestlcoin/electrum-grs/releases/download/v3.2.2/electrum-grs-v3.2.2-setup.exe
Download Windows standalone wallet here: https://github.com/Groestlcoin/electrum-grs/releases/download/v3.2.2/electrum-grs-v3.2.2.exe
Download Windows portable version here: https://github.com/Groestlcoin/electrum-grs/releases/download/v3.2.2/electrum-grs-v3.2.2-portable.exe

Linux wallet instructions:
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/v3.2.2/Electrum-grs-3.2.2.tar.gz
electrum-grs

Source code:
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
Github Source Icons: https://github.com/Groestlcoin/electrum-grs-icons
Github Source locale: https://github.com/Groestlcoin/electrum-grs-locale
#21


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.



If you are an ordinary user of Groestlcoin and simply want the convenience of a web wallet with the security of a real application and support for multi-signature, then Elecrum-GRS is the right choice for you.

Changelog Electrum-GRS 3.2.2:
• 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.

Features
• Encrypted wallet - the file that contains your groestlcoins is protected with a password. You are protected from thieves.
• Deterministic key generation - If you lose your wallet, you can recover it from its seed. You are protected from your own mistakes.
• Instant on - the client does not download the blockchain, it requests that information from a server. No delays, always up-to-date.
• Freedom and Privacy - The server does not store user accounts. You are not tied to a particular server, and the server does not need to know you.
• No scripts - Electrum-GRS does not download any script. A compromised server cannot send you arbitrary code and steal your groestlcoins.
• No single point of failure - The server code is open source, anyone can run a server.
• Transactions are signed locally - Your private keys are not shared with the server. You do not have to trust the server with your money.
• Firewall friendly - The client does not need to open a port, it simply polls the server for updates.
• Free software - Gnu GPL v3. Anyone can audit the code.
• Written in Python - The code is short, and easy to review.
• User Friendly - Support for Groestlcoin URIs, signed URIs and Groestlcoin aliases
• No Lock-In - You can export your private keys and use them in other groestlcoin clients.
• No Downtimes - Electrum-GRS servers are decentralized and redundant. Your wallet is never down.
• Proof Checking - Electrum-GRS Wallet verifies all the transactions in your history using SPV.
• Cold Storage - Keep your private keys offline, and go online with a watching-only wallet. Sign transactions from a computer taht is always offline. Broadcast them from a machine that does not have your keys.
• Multisign - Split the permission to spend your coins between several wallets using parallel BIP32 derivations and P2SH addresses ("2 of 2", "2 of 3"). Compact serialization format for unsigned or partially signed transactions, that includes the BIP32 master public key and derivation needed to sign inputs. Serialized transactions can be sent to cosigners or to cold storage using QR codes

It is appreciated if feedback of the following is provided:
1. Can you receive coins with legacy addresses? (small amounts to avoid losing them)
2. Can you receive coins with bech32 addresses? (small amounts to avoid losing them)
3. Can you receive coins with legacy testnet addresses? (small amounts to avoid losing them)
4. Can you receive coins with bech32 testnet addresses? (small amounts to avoid losing them)
5. Can you send coins with legacy addresses? (small amounts to avoid losing them)?
6. Can you send coins with bech32 addresses? (small amounts to avoid losing them)?
7. Can you send coins with legacy testnet addresses? (small amounts to avoid losing them)?
8. Can you send coins with bech32 testnet addresses? (small amounts to avoid losing them)?
9. Does it automatically detect servers under Tools - Network?
10. Are you able to sweep private keys?
11. Are you able to sign/verify messages?
12. Are you able to encrypt/decrypt messages?

This application is licensed under the GPL version 3. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1. PM me
2. Email: [email protected]
3. Post reports of erros in this topic.

Important:
Store your secret phrase somewhere safe!
The multi-signature and non native segwit addresses starts with a "3" and not with a "F".

Electrum-GRS is available in the Google play store:
https://play.google.com/store/apps/details?id=org.groestlcoin.electrumgrs

Source code:
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
Github Source Icons: https://github.com/Groestlcoin/electrum-grs-icons
Github Source locale: https://github.com/Groestlcoin/electrum-grs-locale
#22


Groestlcoin EasyVanity:This Windows app is built from the ground-up in 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-Style 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.

Note: Groestlcoin addresses consist of random digits and uppercase and lowercase letters, with the exception that the uppercase letter "O", uppercase letter "I", lowercase letter "l", and the number "0" are never used to prevent visual ambiguity.

It is appreciated if feedback of the following is provided:
1. Are you able to create vanity addresses for Groestlcoin?
2. Are you able to create a password protected private key?
3. Are you able to decrypt a password protected key?
4. Are you able to sweep the private keys (using any of our clients)?
5. Are you able to import the private keys (using any of our clients)?
6. Are you able to switch between light/dark theme?

This application is licensed under the MIT There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1.  Email: [email protected]
2.  Reports of errors can also be posted in this topic.

Download the Groestlcoin EasyVanity here:
Installer with Binaries: https://github.com/Groestlcoin/Groestlcoin-EasyVanity/releases/download/1/VanityGenInstaller_WithBinaries.msi
Installer without Binaries: https://github.com/Groestlcoin/Groestlcoin-EasyVanity/releases/download/1/VanityGenInstaller_NoBinaries.msi
Non Installer with binaries: https://github.com/Groestlcoin/Groestlcoin-EasyVanity/releases/download/1/Groestlcoin.EasyVanity.No.Install.zip
Non Installer without binaries: https://github.com/Groestlcoin/Groestlcoin-EasyVanity/releases/download/1/Groestlcoin.EasyVanity.No.Install.No.Binaries.zip

Note: There are two separate installers. Some antivirus software may consider the vanitygen executables that this application uses to be malicious, and as a result we have included an installer that does not contain the Vanitygen files. If the full release causes you trouble, download the Install-Only version and copy the latest windows binaries from https://github.com/Groestlcoin/vanitygen/releases into $InstallDirectory\ProgFiles after installation. We're working hard to negate these issues for a future release.

Source code: https://github.com/Groestlcoin/Groestlcoin-EasyVanity
#23


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.
Groestlcoin Sentinel is a fork of Groestlcoin Samourai Wallet with all spending and transaction building code removed.

Changelog v3.5.02:
• 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

Changelog v2.7.1:
• Added refresh button
• Groestlsight blockexplorer support
• Haptic PIN entry support
• Track Segwit BIP49 YPUBs extended pubkeys
• Sweep P2PKH and Segwit P2SH-P2WPHK amounts into selected account/address
• Use https for blockexplorers

Features
• Open source and unlicensed.
• No Private Keys - Groestlcoin Sentinel only uses Public Keys. It never knows or never asks for your Private Keys.
• Track multiple XPUB's, YPUB's, ZPUB's or Addresses - Add multiple XPUB's, YPUB's, ZPUBS's or addresses to your Groestlcoin Sentinel Watchlist to keep track of balances, transactions, and accept payments into any added wallet or address.
• Deterministically derives Groestlcoin Addresses - Deterministically derive new Groestlcoin addresses associated with your added wallets without needing access or knowledge to your private keys.
• Shareable QR code - Create payment request QR codes with address and amount encoded directly into the image. Share with anyone or any app directly from Groestlcoin Sentinel.
• The most popular Fiat currencies - Groestlcoin Sentinel can convert GRS to your local currency. Supported currencies are: USD, EUR, GBP, CNY, KRW and RUB
• Exchanges - Groestloin Sentinel can pull the current Fiat price from Cryptopia, Bittrex, Binance and Upbit.
• Secure PIN Code protection - Add a secure PIN code to protect access to Groestlcoin Sentinel. Optionally turn on PIN Scramble to help thwart against keylogger attacks.

It is appreciated if feedback of the following is provided:
1. Can you receive coins? (small amounts to avoid losing them)
2. Can you scan a QR code from another phone.
3. Can you broadcast a raw tx?
4. Can you view the transactions on the block explorer?
5. Are you able to export and restore the wallet?
6. Can you add multiple XPUB's or addresses in the wallet?
7. Can you add multiple YPUB's or addresses in the wallet?
8. Can you add multiple ZPUB's or addresses in the wallet?
9. Can you sweep P2PKH (legacy) paperwallet?
10. Can you sweep Segwit BIP49 (P2SH-P2WPHK) paperwallet?
11. Can you sweep Segwit BIP84 (bech32) paperwallet?
12. Does it calculate exchange rates properly in your local currency?

This application is unlicensed. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1.  PM hashengineering on bitcointalk: https://bitcointalk.org/index.php?action=profile;u=155038
2.  Email: [email protected]
3.  Reports of errors can also be posted in this topic.

Groestlcoin sentinel is available in the Google play store:
https://play.google.com/store/apps/details?id=hashengineering.groestlcoin.samourai.sentinel

Source code:
https://github.com/Groestlcoin/groestlcoin-sentinel-android - The Groestlcoin Sentinel source code
#24


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.
Groestlcoin Sentinel is a fork of Groestlcoin Samourai Wallet with all spending and transaction building code removed.

Changelog v3.5.02:
• 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

Changelog v2.7.1:
• Added refresh button
• Groestlsight blockexplorer support
• Haptic PIN entry support
• Track Segwit BIP49 YPUBs extended pubkeys
• Sweep P2PKH and Segwit P2SH-P2WPHK amounts into selected account/address
• Use https for blockexplorers

Features
• Open source and unlicensed.
• No Private Keys - Groestlcoin Sentinel only uses Public Keys. It never knows or never asks for your Private Keys.
• Track multiple XPUB's, YPUB's, ZPUB's or Addresses - Add multiple XPUB's, YPUB's, ZPUBS's or addresses to your Groestlcoin Sentinel Watchlist to keep track of balances, transactions, and accept payments into any added wallet or address.
• Deterministically derives Groestlcoin Addresses - Deterministically derive new Groestlcoin addresses associated with your added wallets without needing access or knowledge to your private keys.
• Shareable QR code - Create payment request QR codes with address and amount encoded directly into the image. Share with anyone or any app directly from Groestlcoin Sentinel.
• The most popular Fiat currencies - Groestlcoin Sentinel can convert GRS to your local currency. Supported currencies are: USD, EUR, GBP, CNY, KRW and RUB
• Exchanges - Groestloin Sentinel can pull the current Fiat price from Cryptopia, Bittrex, Binance and Upbit.
• Secure PIN Code protection - Add a secure PIN code to protect access to Groestlcoin Sentinel. Optionally turn on PIN Scramble to help thwart against keylogger attacks.

It is appreciated if feedback of the following is provided:
1. Can you receive coins? (small amounts to avoid losing them)
2. Can you scan a QR code from another phone.
3. Can you broadcast a raw tx?
4. Can you view the transactions on the block explorer?
5. Are you able to export and restore the wallet?
6. Can you add multiple XPUB's or addresses in the wallet?
7. Can you add multiple YPUB's or addresses in the wallet?
8. Can you add multiple ZPUB's or addresses in the wallet?
9. Can you sweep P2PKH (legacy) paperwallet?
10. Can you sweep Segwit BIP49 (P2SH-P2WPHK) paperwallet?
11. Can you sweep Segwit BIP84 (bech32) paperwallet?
12. Does it calculate exchange rates properly in your local currency?

This application is unlicensed. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1.  PM hashengineering on bitcointalk: https://bitcointalk.org/index.php?action=profile;u=155038
2.  Email: [email protected]
3.  Reports of errors can also be posted in this topic.

Groestlcoin Sentinel is available in the Blackberry World:
https://appworld.blackberry.com/webstore/content/59999358/

Source code:
https://github.com/Groestlcoin/groestlcoin-sentinel-android - The Groestlcoin Sentinel source code
#25


Groestlcoin Sentinel Testnet is the easiest and fastest way to track/receive/watch payments in your offline Groestlcoin Testnet Wallets. Groestlcoin Sentinel Testnet is compatible with any standard Groestlcoin Testnet address, BIP44 TPUB (Extended Public Key) BIP49 UPUB and BIP84 VPUB.



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

Features
• Sweep P2PKH, Segwit BIP49 (P2SH-P2WPHK) and Segwit BIP84 (bech32) amounts into selected account/address
• Broadcast hex tx
• Receive address closes upon receipt of testnet groestlcoins
• Refresh button
• Multiple blockexplorers support
• Haptic PIN entry support
• Open source and unlicensed.
• No Private Keys - Groestlcoin Sentinel Testnet only uses Public Keys. It never knows or never asks for your Private Keys.
• Track multiple TPUB's, UPUB's, VPUB's or Addresses - Add multiple TPUB's, UPUB's, VPUBS's or addresses to your Groestlcoin Sentinel Testnet Watchlist to keep track of balances, transactions, and accept payments into any added wallet or address.
• Deterministically derives Groestlcoin Testnet Addresses - Deterministically derive new Groestlcoin Testnet addresses associated with your added wallets without needing access or knowledge to your private keys.
• Shareable QR code - Create payment request QR codes with address and amount encoded directly into the image. Share with anyone or any app directly from Groestlcoin Sentinel Testnet.
• Secure PIN Code protection - Add a secure PIN code to protect access to Groestlcoin Sentinel Testnet. Optionally turn on PIN Scramble to help thwart against keylogger attacks.

It is appreciated if feedback of the following is provided:
1. Can you receive coins? (small amounts to avoid losing them)
2. Can you scan a QR code from another phone.
3. Can you broadcast a raw tx?
4. Can you view the transactions on the block explorer?
5. Are you able to export and restore the wallet?
6. Can you add multiple TPUB's or addresses in the wallet?
7. Can you add multiple UPUB's or addresses in the wallet?
8. Can you add multiple VPUB's or addresses in the wallet?
9. Can you sweep P2PKH (legacy) paperwallet?
10. Can you sweep Segwit BIP49 (P2SH-P2WPHK) paperwallet?
11. Can you sweep Segwit BIP84 (bech32) paperwallet?

This application is unlicensed. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1.  PM hashengineering on bitcointalk: https://bitcointalk.org/index.php?action=profile;u=155038
2.  Email: [email protected]
3.  Reports of errors can also be posted in this topic.

Groestlcoin sentinel Testnet is available in the Google play store:
https://play.google.com/store/apps/details?id=hashengineering.groestlcoin.samourai.sentinel.testnet

Source code:
https://github.com/Groestlcoin/groestlcoin-sentinel-android - The Groestlcoin Sentinel Testnet source code
#26


Groestlcoin Sentinel Testnet is the easiest and fastest way to track/receive/watch payments in your offline Groestlcoin Testnet Wallets. Groestlcoin Sentinel Testnet is compatible with any standard Groestlcoin Testnet address, BIP44 TPUB (Extended Public Key) BIP49 UPUB and BIP84 VPUB.



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

Features
• Sweep P2PKH, Segwit BIP49 (P2SH-P2WPHK) and Segwit BIP84 (bech32) amounts into selected account/address
• Broadcast hex tx
• Receive address closes upon receipt of testnet groestlcoins
• Refresh button
• Multiple blockexplorers support
• Haptic PIN entry support
• Open source and unlicensed.
• No Private Keys - Groestlcoin Sentinel Testnet only uses Public Keys. It never knows or never asks for your Private Keys.
• Track multiple TPUB's, UPUB's, VPUB's or Addresses - Add multiple TPUB's, UPUB's, VPUBS's or addresses to your Groestlcoin Sentinel Testnet Watchlist to keep track of balances, transactions, and accept payments into any added wallet or address.
• Deterministically derives Groestlcoin Testnet Addresses - Deterministically derive new Groestlcoin Testnet addresses associated with your added wallets without needing access or knowledge to your private keys.
• Shareable QR code - Create payment request QR codes with address and amount encoded directly into the image. Share with anyone or any app directly from Groestlcoin Sentinel Testnet.
• Secure PIN Code protection - Add a secure PIN code to protect access to Groestlcoin Sentinel Testnet. Optionally turn on PIN Scramble to help thwart against keylogger attacks.

It is appreciated if feedback of the following is provided:
1. Can you receive coins? (small amounts to avoid losing them)
2. Can you scan a QR code from another phone.
3. Can you broadcast a raw tx?
4. Can you view the transactions on the block explorer?
5. Are you able to export and restore the wallet?
6. Can you add multiple TPUB's or addresses in the wallet?
7. Can you add multiple UPUB's or addresses in the wallet?
8. Can you add multiple VPUB's or addresses in the wallet?
9. Can you sweep P2PKH (legacy) paperwallet?
10. Can you sweep Segwit BIP49 (P2SH-P2WPHK) paperwallet?
11. Can you sweep Segwit BIP84 (bech32) paperwallet?

This application is unlicensed. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1.  PM hashengineering on bitcointalk: https://bitcointalk.org/index.php?action=profile;u=155038
2.  Email: [email protected]
3.  Reports of errors can also be posted in this topic.

Groestlcoin Sentinel Testnet is available in the Blackberry World:
https://appworld.blackberry.com/webstore/content/60018918/

Source code:
https://github.com/Groestlcoin/groestlcoin-sentinel-android - The Groestlcoin Sentinel source code
#27


Groestlcoin Webwallet: 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.

Changelog 1.4:
• RBF enabled by default
• Bech32 address support added
• Testnet support added

Features
• Offline Compressed & uncompressed Address creation.
• Offline Multisignature Address creation.
• In browser Key (re)generation.
• Send and receive payments.
• Ability to decode transactions, redeem scripts and more offline.
• Build custom transactions offline.
• Sign transactions offline.
• Signatures are deterministic as per RFC 6979 (https://tools.ietf.org/html/rfc6979#section-3.2)
• Broadcast transactions.
• nLockTime support.
• Add custom data to transactions with the use of OP_RETURN.
• Brain wallet support.
• Compatible with Groestlcoin Core
• Offline qrcode creator and scanning tool
• HD (bip32) support
• CHECKLOCKTIMEVERIFY (OP_HOLD) supported for time locked addresses
• Replace by fee (RBF) Support
• Segwit Support

Live version available at https://www.groestlcoin.org/webwallet. But it is recommended to download the webwallet offline and run it on your pc. Open index.html to get started.
The built-in wallet can be used with any (non) existing mailaddress and any password.

It is appreciated if feedback of the following is provided:
1. Are you able to create a compressed address?
2. Are you able to create an uncompressed address?
3. Are you able to create a multisig address?
4. Are you able to receive?
5. Are you able to send?
6. Are you able to decode transactions?
7. Are you able to sign offline transactions?
8. Are you able to broadcast transactions?
9. Are you able to use the RBF option?
10. Are you able to scan the QR code?
11. Are you able to add custom data to transactions with use of OP_RETURN?
12. Are you able to use OP_HODL?
13. Are you able to use the built-in wallet?
14. Are you able to create a BIP49 (P2SH-P2WPHK) address?
15. Are you able to create a BIP84 bech32 address?
16. Are you able to use the Testnet version?

This application is licensed under MIT. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

Warning:
Remember the mailaddress and password you used otherwise you will loose your funds.

The application may have unfound bugs and problems. To leave feedback: 
1. PM me
2. Email: [email protected]
3. Post reports of errors in this topic.

Download the Groestlcoin Webwallet here: https://github.com/Groestlcoin/webwallet/archive/master.zip

Source code: https://github.com/groestlcoin/webwallet
#28


Groestlcoin p2sh paperwallet: A simple groestlcoin paper wallet generator that utilizes Segregated Witness (SegWit) Pay To Witness Public Key Hash (P2WPKH) addresses and transactions.



P2sh paperwallet supports creating p2sh paperwallet 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.

Changelog 0.3.2
• 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.
• Rebranded segwit paperwallet to p2sh paperwallet
• Favicon updated
• Testnet support added
• Groestlcoin Sentinel can sweep funds from private keys and QR codes generated with https://www.groestlcoin.org/p2shpaper.html
• Groestlcoin Sentinel Testnet can sweep funds from private keys and QR codes generated with https://www.groestlcoin.org/p2shpaper.html?testnet=true
• 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.

Live version available at https://www.groestlcoin.org/p2shpaper.html. But it is recommended to download the p2sh paperwallet offline and run it on your pc. Open index.html to get started. You can enable testnet mode by adding ?testnet=true to the end of the url. Example: https://www.groestlcoin.org/p2shpaper.html?testnet=true Or locally: localhost/webwallet/index.html?testnet=true

It is appreciated if feedback of the following is provided:
1. Are you able to generate p2sh addresses?
2. Are you able to sweep p2sh private key?
3. Are you able to scan with webcam?
4. Are you able to generate bulk keys?
5. Are you able to validate private keys and to view corresponding segwit address, public key and redeem script on the details section?

There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1. PM me
2. Email: [email protected]
3. Post reports of errors in this topic.

Download the Groestlcoin Webwallet here: https://github.com/Groestlcoin/segwitaddress/archive/master.zip

Source code: https://github.com/Groestlcoin/segwitaddress
#29


Groestlcoin bech32 paperwallet: A simple groestlcoin paper wallet generator that utilizes Native Segregated Witness (SegWit) Pay To Witness Public Key Hash (P2WPKH) addresses and transactions.



Bech32 paperwallet supports creating bech32 paperwallet 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 https://www.groestlcoin.org/bech32paper.html
• Groestlcoin Sentinel Testnet can sweep funds from private keys and QR codes generated with https://www.groestlcoin.org/bech32paper.html?testnet=true
• Electrum-GRS can import private keys using the console and the importprivkey() command. Import as native(bech32) segwit: importprivkey('p2wpkh:KzTLBvC6mNudLBjEmwYCuk3jrZ7sZS8CzFDzcrwnDM2CVpH8vNAn')
• Electrum-GRS Testnet can import private keys using the console and the importprivkey() command. Import as native(bech32) segwit: importprivkey('p2wpkh:cNNDi1AT8XNng2wJ5HNFN41toufU9XZ2bW8MGi7c9SGw4hnMuASk')
• Keypair generation with QR Codes
• Bulk address generator
• Key Sweeping Tool to move all funds belonging to a single SegWit private key.

Live version available at https://www.groestlcoin.org/bech32paper.html. But it is recommended to download the bech32 paperwallet offline and run it on your pc. Open index2.html to get started. You can enable testnet mode by adding ?testnet=true to the end of the url. Example: https://www.groestlcoin.org/bech32paper.html?testnet=true Or locally: localhost/webwallet/index2.html?testnet=true

It is appreciated if feedback of the following is provided:
1. Are you able to generate bech32 addresses?
2. Are you able to sweep bech32 private key?
3. Are you able to scan with webcam?
4. Are you able to generate bulk keys?
5. Are you able to validate private keys and to view corresponding segwit address, public key and redeem script on the details section?

There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1. PM me
2. Email: [email protected]
3. Post reports of errors in this topic.

Download the Groestlcoin Webwallet here: https://github.com/Groestlcoin/segwitaddress/archive/master.zip

Source code: https://github.com/Groestlcoin/segwitaddress
#30


GRSPay Testnet: a free and open-source cryptocurrency payment processor which allows you to receive payments in Groestlcoin Testnet with no fees, transaction cost or a middleman.



GRSPay Testnet is a non-custodial invoicing system which eliminates the involvement of a third-party. Payments with GRSPay Testnet go directly to your wallet, which increases the privacy and security. Your private keys are never uploaded to the server. There is no address re-use, since each invoice generates a new address deriving from your tpubkey or vpubkey.

GRSPay Testnet is available at https://testnet.grspay.com/
https://www.youtube.com/watch?v=c7s3zZnlQ6M

Features
• Direct, P2P Groestlcoin Testnet payments
• Lightning Network Testnet support coming soon
• Complete control over private keys
• Enchanced privacy
• SegWit Testnet support
• Process payments for others
• Payment buttons
• Point of sale
• No transaction fees (other than those for the crypto networks)
• No processing fees
• No middleman
• No KYC
• The software is built in C#
• You can run GRSPay Testnet as a self-hosted solution on your own server or use a our host. The self-hosted solution allows you not only to attach an unlimited number of stores (and soon use the Lightning Network Testnet) but also become the payment processor for others.
• Open Source - MIT license

FAQ
### How to use WooCommerce store with GRSPay Testnet?
https://www.youtube.com/watch?v=qNMTDEPhWhY

### Does GRSPay Testnet need my private key?

Absolutely not. The fact that GRSPay Testnet never needs access to your master private key for on-chain transactions is a huge security advantage. Even if our server gets hacked, your funds from the on-chain transactions are always safe. Securing your on-chain funds, comes down to your own security.
When we will support lightning node, GRSPay Testnet technically will have access to the keys (macarons) of your LN.

### Address re-use - How GRSPay Testnet creates a different address?

GRSPay Testnet generates a different address for each invoice. The address is derived from your tpubkey or vpubkey. Your private keys are never uploaded or required by GRSPay Testnet. The software only needs your extended public key. You can create your private key in your software or hardware wallet and import the public key (tpub/vpub) into GRSPay Testnet so that it can derive addresses from it. Meanwhile, you should stick to the best practices for protecting your private key.

### What e-commerce integrations are available?

Currently, GRSPay Testnet has integrations with the following e-commerce platforms:
- WordPress / WooCommerce
- Magneto
- Drupal
- Prestashop
- Custom integration

### Does GRSPay Testnet Support Lightning Network Testnet?

No not yet but coming soon.

## Invalid Status Code:301 when pairing the store with GRSPay Testnet.

Please make sure to enter the URL of the host you're trying to pair with correctly, including the HTTP(s) part. For example https://testnet.grspay.com

## Invalid derivation scheme

If you're getting this error, this means that you have not connected your wallet to GRSPay Testnet. In Store>Settings> Derivation Scheme, on the right-hand side click modify and set up your derivation scheme correctly.

It is appreciated if feedback of the following is provided:
1. Are you able to register at GRSPay Testnet?
2. Are you able to create a store?
3. Are you able to create an invoice?
4. Are you able to create a POS?
5. Are you able to receive payments through GRSPay Testnet?
6. Are you able to setup your derivation scheme?
7. Are you able to setup 2 factor authentication?

This application is licensed under MIT. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1. PM me
2. Email: [email protected]
3. Post reports of errors in this topic.

Source code:
GRSPay: https://github.com/Groestlcoin/btcpayserver - GRSPay code