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Android Electrum-GRS 4.0.2 released

Started by jackielove4u, September 22, 2020, 08:41:59 PM

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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 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.

• 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 that 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

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.

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:

Source code:
GitHub Source server:
Github Source server installer:
Github Source client: