Digital signatures in browser with MetaMask and Ethereum keys

Cryptonomica launched a web application for digital signatures (signing and signatures verification) using MetaMask plugin for browsers, Ethereum keys and Cryptonomica identity verification: https://cryptonomica.net/eth-sign

You do not need ETH to sign or to verify signature, just MetaMask and Ethereum key.

Information about key owner is read from cryptonomica smart contract that keeps information about verified keys.

To store key information in smart contract you can verify your identity via Cryptonomica.