GreenAddress
GreenAddress is a multi-signature wallet that is very user friendly and has extremely good security. Private keys are never held by the third party server side. Payments have to be approved by Green Address itself. A positive in some way as it provides the same restrictions as traditional banks on large transfers.
Contents
Green addresses was a proposed use of special trusted ECDSA keypairs that to indicate the origin of funds to a recipient. Assuming the recipient trusts the operator of the keypair to not attempt a double spend, the recipient may treat the funds as confirmed the moment they arrive. This proposal is generally considered a bad idea and not advisable to implement.
Main information
- Platforms: Web, Android, iOS, Chrome Extension
- Validation Type: SPV
- Wallet Features: Hierarchical Deterministic, Open Source, 2 Factor Authentication, Multi-Signature
- Url: https://www.cryptocompare.com/wallets/green-address/
- Anonymity: Medium
- Security: Third Party Encrypted
- Coins: BTC
- Source Code Url: https://github.com/greenaddress/GreenBits
- Ease Of Use: Easy
Description
Green Address is a handy wallet with multi-signature, enhanced security and privacy. Your keys are not sent to servers, even in encrypted form. For security reasons, you should always use a 2-factor authentication and browser extension or Android app.
As an example, assume website Z accepts incoming Bitcoin payments, but also trusts the green address published by Mt. Gox. Customer C wants to withdraw funds from Mt. Gox and send them to a payment address of website Z. A customer who does a withdrawal from Mt. Gox could click the use green address checkbox, which will result in the payment being sent to the “green address” derived from the special keypair as an intermediate step before forwarding the payment to site Z. Site Z can confirm that the payment passed through Mt. Gox’s keypair and trust the payment as confirmed immediately, since it knows that the only party who could potentially perform an attack to reverse the payment is Mt. Gox.
The concept originated on the Bitcoin Talk forum in 2011 and was discussed in two threads[1]. Since then, it was implemented by Instawallet and Mt. Gox, both of which have since been compromised and closed.
Wallet Features
- Open source clients for both desktop and mobile
- HD/BIP0032
- Per-transaction 2FA via multisignature, of 4 different kinds: email, sms, robot call, Google Authenticator
- 2-of-2 multisig accounts: Create accounts that can take advantage of GreenAddress’ trusted-third-party instant confirmations. Account recovery without access to GreenAddress is achieved with pre-generated nLockTime transactions (which must be received, typically via email, from GreenAddress on a regular basis).
- 2-of-3 multisig accounts: Create accounts that allow you to access your funds at any time even without access to GreenAddress, using an additional offline recovery key (which only needs to be saved once).
- Transaction information within 2FA message
- BIP0039 mnemonics
- Receive or Send/Tip password protected Bitcoins with BIP0038 (Facebook, Email, Reddit)
- Never reuses the same address which improves both privacy and security
- Easy to use, fast and convenient
Criticism
Confusion between wallet/controller and owner
Bitcoin signatures do not imply any particular legal origin of bitcoins, and when the signature is used to imply some origin, it seems to perpetuate this myth[2].
Blockchain spam
In order to actually use green addresses, it is necessary to create an extra transaction to the special ECDSA keypair before then forwarding it on to its final destination.
External links
- What Are Green Addresses Q&A on StackExchange
- How To Create A Bitcoin Multisig Wallet
- Green Address Official website
- Blog
- FAQ
- About
- Infographics
- Github
- Faceboook
- @GreenAdress on Twitter
- Testnet
- Android Google Play
- F-Droid Open Source Repo
- iTunes App Store for iOS