public static bool TryComputeHash(ReadOnlySequence <byte> sequence, ReadOnlySpan <byte> key, Span <byte> destination)
{
if (destination.Length < 32)
{
throw new ArgumentOutOfRangeException(nameof(destination));
}
Span <byte> extendedKey = stackalloc byte[_blockLength];
if (key.Length > _blockLength)
{
Sha2_256.TryComputeHash(key, extendedKey);
}
else
{
BytesOperations.Copy(key, extendedKey, Math.Min(key.Length, extendedKey.Length));
}
Span <byte> ixor = stackalloc byte[_blockLength];
BytesOperations.Xor(_ipad, extendedKey, ixor);
Span <byte> oxor = stackalloc byte[_blockLength];
BytesOperations.Xor(_opad, extendedKey, oxor);
Span <byte> ihash = stackalloc byte[32];
using (var incrementalHash = IncrementalHash.CreateHash(HashAlgorithmName.SHA256))
{
incrementalHash.AppendData(ixor);
foreach (var segment in sequence)
{
incrementalHash.AppendData(segment.Span);
}
incrementalHash.TryGetHashAndReset(ihash, out _);
}
using (var incrementalHash = IncrementalHash.CreateHash(HashAlgorithmName.SHA256))
{
incrementalHash.AppendData(oxor);
incrementalHash.AppendData(ihash);
return(incrementalHash.TryGetHashAndReset(destination, out _));
}
}
public static bool Verify(ReadOnlyMemory <byte> publicKey, ReadOnlyMemory <byte> signature, ReadOnlySequence <byte> sequence)
{
using var ecdsa = ECDsa.Create();
ecdsa.ImportSubjectPublicKeyInfo(publicKey.Span, out var _);
return(ecdsa.VerifyHash(Sha2_256.ComputeHash(sequence).AsSpan(), signature.Span));
}
public static byte[] Sign(ReadOnlyMemory <byte> privateKey, ReadOnlySequence <byte> sequence)
{
using var ecdsa = ECDsa.Create();
ecdsa.ImportPkcs8PrivateKey(privateKey.Span, out var _);
return(ecdsa.SignHash(Sha2_256.ComputeHash(sequence)));
}
