The sign method calculates an Ethereum specific signature with: sign(keccak256("\x19Ethereum Signed Message:\n" + len(message) + message)))
.
By adding a prefix to the message makes the calculated signature recognisable as an Ethereum specific signature. This prevents misuse where a malicious DApp can sign arbitrary data (e.g. transaction) and use the signature to impersonate the victim.
Note the address to sign with must be unlocked.
account, message
DATA
, 20 Bytes - address.DATA
, N Bytes - message to sign.DATA
: Signature
// Request
curl -X POST --data '{"jsonrpc":"2.0","method":"eth_sign","params":["0x9b2055d370f73ec7d8a03e965129118dc8f5bf83", "0xdeadbeaf"],"id":1}'
// Result
{
"id":1,
"jsonrpc": "2.0",
"result": "0xa3f20717a250c2b0b729b7e5becbff67fdaef7e0699da4de7ca5895b02a170a12d887fd3b17bfdce3481f10bea41f45ba9f709d39ce8325427b57afcfc994cee1b"
}
An example how to use solidity ecrecover to verify the signature calculated with eth_sign
can be found here. The contract is deployed on the testnet Ropsten and Rinkeby.