Android Simple Groestlcoin released

Started by gruve_p, June 23, 2016, 06:54:48 AM

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gruve_p



Simple Groestlcoin is a standalone wallet for Android devices which does not depend on any centralized service and gives you full control over your precious groestlcoins. Its main advantages over the original Groestlcoin Android client include support for HD wallet.



Features
• A single-page application which allows you to store your Groestlcoins securely and transfer them easily.
• It is an HD wallet which means your balance and full transaction history can always be restored using a single mnemonic code should anything bad happen to your device.
• This wallet is intended for mobile devices, hence it does not store a full Blockchain but instead acquires all the relevant data from random groestlcoin nodes using an SPV technique.
• Self-Destruction functionality. Set up a secret code which you can use to self-destruct all wallet data. Use your mnemonic code to restore your wallet again.
• Open source under GPL v3 License
• Wallet only needs to be backed up once, on initial creation.
• Wallet backup consists of simple list of 12 common words (BIP-0039).
• No servers just the Groestlcoin network using the Groestlcoinj library.
• Simple and intuitive user interface.
• No worrying about losing private keys any more - use your "wallet words" (seed phrase) to restore them.

Mnemonic code
Simple Groestlcoin is a so called HD wallet: all Groestlcoin addresses and private keys come from a single mnemonic code which is essentially a phrase comprising of 12 random words. Please remember: whoever knows your mnemonic code also fully controls your Groestlcoins so it should be kept private at all times.
Also, in case if you lose your device or forget your wallet password only mnemonic code can get your Groestlcoins back, it's that important! Ideally one of the following actions should be taken once a new wallet is created:
• Either write your mnemonic code on a piece of paper and store it in a really secure place.
• Or encrypt your mnemonic code using wallet password as a key and store it wherever you like. For that you can use AES-256 text encryption in Secret Space Encryptor which is a popular open source Android app.

Unconfirmed transactions
Here's a simple heuristic: treat any unconfirmed incoming transaction as if it does not exist yet. There are a lot of technical reasons for this and the rule applies to all wallets, not just to Simple Groestlcoin Wallet. Just wait for at least one confirmation and you'll be fine.

Transaction fees
Every transaction you send must have some fee attached to it. Fee goes not to wallet developer but to Groestlcoin miners who include transactions in blocks and thus give them confirmations. The higher fee you choose the faster transaction will be confirmed.

Wallet addresses
Due to privacy considerations wallet has not one but many addresses. In fact, wallet's default address gets changed on every new incoming transaction. Never worry about it as all the old wallet addresses stay valid forever and you can use any of them to receive funds.

In case you lose your password...
It's important to understand that Simple Groestlcoin Wallet is not a centralized service so you can't regain access to your funds by just providing an email or something like that. Here you'll need to restore a wallet using your mnemonic code and this is how to do it step by step:
1. Erase all current wallet data if you know how to do that (such an option is typically available in System Settings), otherwise just reinstall an application from scratch.
2. Open fresh application and you'll be given an option to restore your wallet instead of creating a new one, choose it and enter your mnemonic code as well as new wallet password.

It 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.  Can you scan a QR code from another phone.
4.  Can you request coins via email or other android service?
5.  How long does it take to sync the blockchain?
6.  How much space does it take up on your phone?
7.  Does it calculate exchange rates properly?
8.  Does the self-destruction function work properly?

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 note: restored wallet will appear empty at first and that is completely normal as it needs some time to catch up with network.

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.

Simple Groestlcoin is available in the Google play store:
https://play.google.com/store/apps/details?id=hashengineering.groesltcoin.btcontract_wallet

Source code:
https://github.com/Groestlcoin/groestlcoinj - Groestlcoin Java Library (for the Android App and possibly other software)
https://github.com/GroestlCoin/btcontract-wallet - The Simple Groestlcoin Android Wallet Source code