signDigest method
Signs a given digest using the private key and a specified value of 'k'.
Implementation
ECDSASignature signDigest(
{required List<int> digest,
List<int>? entropy,
required BigInt k,
bool truncate = false}) {
final digestInt =
_truncateAndConvertDigest(digest, generator, truncate: truncate);
final sign = privateKey.sign(digestInt, k);
return sign;
}