/// <inheritdoc />
public override bool TrySignHash(ReadOnlySpan <byte> privateKey, ReadOnlySpan <byte> hash, Span <byte> destination,
out int bytesWritten, ReadOnlySpan <byte> domain = default)
{
if (destination.Length < SignatureLength)
{
bytesWritten = 0;
return(false);
}
EnsureInitialised();
// TODO: Generate random key if null
// EnsurePrivateKey();
var blsSecretKey = default(Bls384Interop.BlsSecretKey);
int bytesRead;
unsafe
{
fixed(byte *privateKeyPtr = privateKey)
{
bytesRead = Bls384Interop.SecretKeyDeserialize(ref blsSecretKey, privateKeyPtr, privateKey !.Length);
}
}
if (bytesRead != privateKey.Length)
{
throw new Exception($"Error deserializing BLS private key, length: {bytesRead}");
}
var blsSignature = default(Bls384Interop.BlsSignature);
int result;
if (domain.Length > 0)
{
if (hash.Length != HashLength)
{
throw new ArgumentOutOfRangeException(nameof(hash), hash.Length,
$"Hash with domain must be {HashLength} bytes long.");
}
if (domain.Length != DomainLength)
{
throw new ArgumentOutOfRangeException(nameof(domain), domain.Length,
$"Domain must be {DomainLength} bytes long.");
}
var hashWithDomain = new Span <byte>(new byte[HashLength + DomainLength]);
hash.CopyTo(hashWithDomain);
domain.CopyTo(hashWithDomain.Slice(HashLength));
unsafe
{
fixed(byte *hashPtr = hashWithDomain)
{
result = Bls384Interop.SignHashWithDomain(ref blsSignature, ref blsSecretKey, hashPtr);
}
}
}
else
{
unsafe
{
fixed(byte *hashPtr = hash)
{
result = Bls384Interop.SignHash(ref blsSignature, ref blsSecretKey, hashPtr, hash.Length);
}
}
}
// ReadOnlySpan<byte> hashToSign;
// if (domain.Length > 0)
// {
// var combined = new byte[2 * InitialXPartLength];
// var combineSuccess = TryCombineHashAndDomain(hash, domain, combined, out var combineBytesWritten);
// if (!combineSuccess || combineBytesWritten != 2 * InitialXPartLength)
// {
// throw new Exception("Error combining the hash and domain.");
// }
// hashToSign = combined;
// }
// else
// {
// hashToSign = hash;
// }
// unsafe
// {
// fixed (byte* hashPtr = hash)
// {
// result = Bls384Interop.SignHash(out blsSignature, blsSecretKey, hashPtr, hash.Length);
// }
// }
if (result != 0)
{
throw new Exception($"Error generating BLS signature for hash. Error: {result}");
}
unsafe
{
fixed(byte *destinationPtr = destination)
{
bytesWritten = Bls384Interop.SignatureSerialize(destinationPtr, SignatureLength, ref blsSignature);
}
}
if (bytesWritten != SignatureLength)
{
throw new Exception($"Error serializing BLS signature, length: {bytesWritten}");
}
return(true);
}