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.

Changelog Electrum-GRS 4.0.2:
• Lightning Network support (experimental)
• Our implementation of Lightning relies on Electrum-GRS servers to query channel states. Since servers can lie about the state of a channel, users should either use a server that they trust, or setup a private watchtower (see below). A watchtower is also recommended for lightning wallets that remain offline for extended periods of time (the default CSV 'to_self_delay' is 1 week). Please note that Electrum Personal Server (EPS) cannot be used with lightning wallets, because channels funding addresses are arbitrary.
• Lightning funds cannot be restored from seed. Instead, users need to create static backups of their channels. Static backups cannot be used to perform lightning transactions, they can only be used to trigger a remote-force-close of a channel.
• Lightning-enabled wallet files must not be copied. Instead, a backup of the wallet can be created from the Qt menu, and it will contain static backups of all its channels. Backups can also be exported for each channel (e.g. via QR code), and imported in another wallet. Since backups are encrypted with a key derived from the wallet's xpub, they can only be imported into another instance of the same wallet, or a watch-only version of it. The force-close is not triggered automatically when the backup is imported; imported backups can live inside a wallet file.
• Lightning can be enabled in the GUI (Wallet>Information) or from the CLI (init_lightning). Lightning is currently restricted to HD p2wpkh wallets (including watch-only and hardware wallets). The Qt GUI, CLI/RPC, and the kivy GUI (Android) all have LN support, with feature-richness in that order.
• LN protocol details: dataloss_protect and static_remotekey are required; varonion and payment_secret are implemented, MPP not yet. Channels are not announced ('private'), forwarding is disabled. We do not serve gossip queries, only consume them.
• Submarine swaps: the GUI integrates a service that offers atomically exchanging on-chain and lightning groestlcoins for a fee. Groestlcoin development team runs a central server for this, powered by the Boltz backend.
• Watchtowers: Electrum-GRS can run a local watchtower (GUI setting), or it can connect to a remote watchtower. A watchtower contains pre-signed transactions and does not need your private keys. A local watchtower will watch your channels whenever an Electrum-GRS instance is running, without needing access to your wallet file. An Electrum-GRS daemon can be configured to be used as a remote watchtower by setting 'watchtower_address', 'watchtower_user' and 'watchtower_password'.
• Partially Signed Bitcoin Transactions (PSBT, BIP-174) are supported. The previous Electrum-GRS partial transaction format is no longer supported, i.e. this is an incompatible change. Users should make sure that all instances of Electrum-GRS they use to co-sign or offline sign, are updated together.
• Compatibility with latest Trezor fw
• Libsecp256k1 is now required (previously optional). python-ecdsa remains a dependency but it is now only used for DNSSEC.
• Added: either one of pycryptodomex or cryptography is now required, mainly due to LN (previously pycryptodomex was optional, for fast AES)
• Removed: jsonrpclib-pelix, the JSON-RPC library used for CLI/daemon
• Separation between output selection and transaction finalization.
• Coin selection moved to the Coins tab, and it affects all txns, e.g. RBF fee-bumping, LN channel opens, submarine swaps.
• Editable tx preview dialog that allows e.g. changing the locktime, toggling RBF, and manual coinjoins.
• HTTP PayServer: The configuration of a groestlcoin-accepting website using Electrum-GRS has been simplified and requires fewer steps (see documentation). The Payserver supports BIP70 and Lightning payments.
• The API of several CLI/RPC commands have changed, and several new commands have been introduced (mainly for LN).
• The .tar.gz source dist is now built reproducibly. Relatedly, we no longer distribute a .zip sdist.
• We now grind low R for ECDSA signatures to match groestlcoind
• Lots and lots of other minor bugfixes and improvements.
• We now build two APKs, one for ARMv7 and one for ARMv8
• The kivy GUI now supports importing BIP39 seeds
• Each wallet on kivy now can have a separate generic password, using which the wallet files are encrypted. An optional PIN, shared among all wallets, can be added to get prompted for spends.

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.

Source code:
GitHub Source server: https://github.com/Groestlcoin/electrumx
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