internal static byte[] Digest(byte[] data)
{
Sha512tDigest digest = new Sha512tDigest(256);
digest.BlockUpdate(data, 0, data.Length);
byte[] output = new byte[32];
digest.DoFinal(output, 0);
return(output);
}
/// <summary>
/// Hashes a list of byte arrays, prefixing each one with its length.
/// </summary>
public byte[] Sum(byte[] domain, params byte[][] datas)
{
using (var stream = new MemoryStream())
{
byte[] ulongBytes;
foreach (var data in datas)
{
ulongBytes = this.UInt64ToBytes((ulong)data.Length);
stream.Write(ulongBytes, 0, ulongBytes.Length);
stream.Write(data, 0, data.Length);
}
ulongBytes = this.UInt64ToBytes((ulong)domain.Length);
stream.Write(ulongBytes, 0, ulongBytes.Length);
stream.Write(domain, 0, domain.Length);
var result = stream.ToArray();
byte[] hash;
var sha = new Sha512tDigest(256);
try
{
sha.BlockUpdate(result, 0, result.Length);
hash = new byte[sha.GetDigestSize()];
sha.DoFinal(hash, 0);
}
finally
{
sha.Finish();
}
return(hash);
}
}
public void Should_GeneratePointOnCurve_When_RandomHashesArePassed()
{
var curveParams = NistNamedCurves.GetByName("P-256");
var swu = new Swu(((FpCurve)curveParams.Curve).Q, curveParams.Curve.B.ToBigInteger());
var rng = new SecureRandom();
var sha = new Sha512tDigest(256);
var random = new byte[32];
for (int i = 0; i <= 10000; i++)
{
var hash = new byte[32];
rng.NextBytes(random);
sha.BlockUpdate(random, 0, random.Length);
sha.DoFinal(hash, 0);
var(x, y) = swu.HashToPoint(hash);
Assert.True(curveParams.Curve.CreatePoint(x, y).IsValid());
sha.Reset();
}
}
protected override byte[] HashFinal()
{
_digest.DoFinal(HashValue, 0);
return(HashValue);
}
