Electrum-GRS wallet

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.

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

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

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.

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.

OSX:
Download the OSX wallet: 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

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