<b>NOTE:</b> This app is no longer maintained (its source repo was archived). Wallet that uses multisig to improve security (adding 2 factor for instance or limits) and Hierarchical Deterministic addresses (see <a href="https://en.bitcoin.it/wiki/BIP_0032">BIP32</a>). It offers the advantages of a web wallet: * Ubiquitously available * Social/email/sms integration * Two factor authentication * Transactions limits/restrictions * Greenaddress instant transaction and the advantages of a local software wallet like Electrum: * Mnemonic seed backup once and forget * Your private keys are never on the server, not even encrypted * No long wait to synchronize the full client with the Bitcoin blockchain See <a href="https://greenaddress.it">their website</a> and <a href="https://greenaddress.it/faq their">FAQ</a> for more information. Supports NFC for login and QR code scanning for login and transactions.