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 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 ! --from '• 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 file2. 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 usersIt is appreciated if feedback of the following is provided:1. Can you receive coins? (small amounts to avoid losing them)2. Can you send coins?3. Does the cosigner pool work when using a multi-signature wallet?4. Does the virtual keyboard work when it asks to enter your wallet password?5. Does it automatically detect electrum1.groestlcoin.org and electrum2.groestlcoin.org under Tools - Network?6. Are you able to sweep private keys?7. Are you able to sign/verify messages?8. 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 me2. Email: groestlcoin@gmail.com3. Post reports of erros in this topic.Important:Store your secret phrase somewhere safe!The multi-signature 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 Linux wallet here: https://github.com/GroestlCoin/electrum-grs/releases/download/v2.5.4/Electrum-GRS-2.5.4_Linux_x86_64-Installer.bin Download the OSX PKG wallet here: https://github.com/GroestlCoin/electrum-grs/releases/download/v2.5.4/Electrum-GRS-2.5.4-Installer.pkg Download Windows wallet here: https://github.com/GroestlCoin/electrum-grs/releases/download/v2.5.4/Electrum-grs-2.5.4-Windows-setup.exe Source code:GitHub Source server: https://github.com/Groestlcoin/electrum-grs-server Github Source client: https://github.com/Groestlcoin/electrum-grs