public static bool DoVerifyEcDsa(
IEnumerable <BufLen> bufs,
I2PSigningPublicKey key,
I2PSignature signed,
IDigest digest,
X9ECParameters ecparam)
{
if (!SupportedSignatureType(signed.Certificate.SignatureType))
{
throw new NotImplementedException();
}
foreach (var buf in bufs)
{
digest.BlockUpdate(buf.BaseArray, buf.BaseArrayOffset, buf.Length);
}
var hash = new byte[digest.GetDigestSize()];
digest.DoFinal(hash, 0);
var param = new ECDomainParameters(ecparam.Curve, ecparam.G, ecparam.N, ecparam.H);
var pk = new ECPublicKeyParameters(ecparam.Curve.DecodePoint(key.ToByteArray()), param);
var dsa = new Org.BouncyCastle.Crypto.Signers.DsaSigner();
var sigsize = signed.Certificate.SignatureLength;
var r = new BigInteger(1, signed.Sig.BaseArray, signed.Sig.BaseArrayOffset, sigsize / 2);
var s = new BigInteger(1, signed.Sig.BaseArray, signed.Sig.BaseArrayOffset + sigsize / 2, sigsize / 2);
dsa.Init(false, pk);
var result = dsa.VerifySignature(hash, r, s);
DebugUtils.LogDebug("DoVerifyEcDsa: " + result.ToString() + ": " + digest.ToString());
return(result);
}
public static byte[] DoSignEcDsa(
IEnumerable <BufLen> bufs,
I2PSigningPrivateKey key,
IDigest digest,
X9ECParameters ecparam,
int sigsize)
{
foreach (var buf in bufs)
{
digest.BlockUpdate(buf.BaseArray, buf.BaseArrayOffset, buf.Length);
}
var hash = new byte[digest.GetDigestSize()];
digest.DoFinal(hash, 0);
var param = new ECDomainParameters(ecparam.Curve, ecparam.G, ecparam.N, ecparam.H);
var pk = new ECPrivateKeyParameters(key.ToBigInteger(), param);
var s = new Org.BouncyCastle.Crypto.Signers.ECDsaSigner();
s.Init(true, new ParametersWithRandom(pk));
var sig = s.GenerateSignature(hash);
var result = new byte[sigsize];
var b1 = sig[0].ToByteArrayUnsigned();
var b2 = sig[1].ToByteArrayUnsigned();
// https://geti2p.net/en/docs/spec/common-structures#type_Signature
// When a signature is composed of two elements (for example values R,S),
// it is serialized by padding each element to length/2 with leading zeros if necessary.
// All types are Big Endian, except for EdDSA, which is stored and transmitted in a Little Endian format.
// Pad msb. Big endian.
Array.Copy(b1, 0, result, sigsize / 2 - b1.Length, b1.Length);
Array.Copy(b2, 0, result, sigsize - b2.Length, b2.Length);
DebugUtils.LogDebug("DoSignEcDsa: " + digest.ToString() + ": Used.");
return(result);
}