/// <summary>
/// Sign the message with <see cref="ECKeyPair"/>. Only recovery id 0 or 1 is accepted, otherwise the method will continue to retry to sign til get recovery id is 0 or 1.
/// </summary>
/// <param name="message">message to be signed</param>
/// <param name="keyPair"></param>
/// <param name="needToHash">set true if the message to be hashed before signing. If it is true, hashed first,then sign. If it is false, signed directly.</param>
/// <returns></returns>
public static SignatureData SignMessage(byte[] message, ECKeyPair keyPair, bool needToHash)
{
var publicKey = keyPair.PublicKey;
byte[] messageHash;
messageHash = needToHash ? CryptoUtils.Blake2b(message) : message;
int recId = -1;
ECDSASignature sig;
sig = keyPair.Sign(messageHash);
for (int i = 0; i < 4; i++)
{
var k = RecoverFromSignature(i, sig, messageHash);
if (k != null && k.Equals(publicKey))
{
recId = i;
break;
}
}
if (recId == -1)
{
throw new SignException("Sign the data failed.");
}
if (recId == 2 || recId == 3)
{
throw new SignException("Recovery is not valid for VeChain MainNet.");
}
byte v = (byte)recId;
var r = ByteUtils.ToBytesPadded(sig.R, 32);
var s = ByteUtils.ToBytesPadded(sig.S, 32);
return(new SignatureData(v, r, s));
}