Serialize message signatures

[kumavis]

they come out in this format:

function concatSig(v, r, s) {
  r = ethUtil.fromSigned(r)
  s = ethUtil.fromSigned(s)
  v = ethUtil.bufferToInt(v)
  r = ethUtil.toUnsigned(r).toString('hex')
  s = ethUtil.toUnsigned(s).toString('hex')
  v = ethUtil.stripHexPrefix(ethUtil.intToHex(v))
  return ethUtil.addHexPrefix(r.concat(s, v).toString("hex"))
}

[axic]

@fanatid are r and s in two's complement format in secp256k1.sign()?

@kumavis I don't think the above should need to use fromSigned/toUnsigned conversion. Also it converts it to the format the new geth is using (the one uses v-27).

[kumavis]

this is just copy pasta from lightwallet https://github.com/ConsenSys/eth-lightwallet/blob/master/lib/signing.js
sorry im not very familiar with this one

[kumavis]

obv we should include a verify method

[fanatid]

@axic secp256k1.sign return r/s as unsigned numbers that lower than n (FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141)