bool IGangCryptoVerificationService.Verify(
GangCryptoParameters parameters,
ReadOnlySpan <byte> data,
ReadOnlySpan <byte> signature
)
{
if (parameters is null)
{
throw new ArgumentNullException(nameof(parameters));
}
var rsa = RSA.Create();
rsa.ImportParameters(new RSAParameters
{
Exponent = parameters.GetByteArray("-2"),
Modulus = parameters.GetByteArray("-1")
});
return(rsa.VerifyData(
data.ToArray(),
signature.ToArray(),
HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1
));
}
bool IGangCryptoVerificationService.Verify(
GangCryptoParameters parameters,
ReadOnlySpan <byte> data,
ReadOnlySpan <byte> signature
)
{
if (parameters is null)
{
throw new ArgumentNullException(nameof(parameters));
}
var curveType = parameters.GetInt("-1");
var curve = curveType switch
{
1 => ECCurve.NamedCurves.nistP256,
_ => throw new Exception($"Unknown curve type {curveType}"),
};
var ecDsa = ECDsa.Create(new ECParameters
{
Curve = curve,
Q = new ECPoint
{
X = parameters.GetByteArray("-2"),
Y = parameters.GetByteArray("-3")
}
});
using var ms = new MemoryStream(signature.ToArray());
var header = ms.ReadByte();
var b1 = ms.ReadByte();
var markerR = ms.ReadByte();
var b2 = ms.ReadByte();
var vr = new byte[b2];
ms.Read(vr, 0, vr.Length);
vr = RemoveNegativeFlag(vr);
var markerS = ms.ReadByte();
var b3 = ms.ReadByte();
var vs = new byte[b3];
ms.Read(vs, 0, vs.Length);
vs = RemoveNegativeFlag(vs);
var parsedSignature = new byte[vr.Length + vs.Length];
vr.CopyTo(parsedSignature, 0);
vs.CopyTo(parsedSignature, vr.Length);
return(ecDsa.VerifyData(
data.ToArray(),
parsedSignature,
HashAlgorithmName.SHA256));
}
