public void Verify(Key key, SignMessage msg)
{
string alg = FindAttr("alg", msg).AsString();
COSE.EdDSA eddsa;
IDigest digest;
IDigest digest2;
switch (alg)
{
case "RS256":
case "ES256":
case "PS256":
case "HS256":
digest = new Sha256Digest();
digest2 = new Sha256Digest();
break;
case "RS384":
case "ES384":
case "PS384":
case "HS384":
digest = new Sha384Digest();
digest2 = new Sha384Digest();
break;
case "RS512":
case "ES512":
case "PS512":
case "HS512":
digest = new Sha512Digest();
digest2 = new Sha512Digest();
break;
case "EdDSA":
digest = null;
digest2 = null;
break;
default:
throw new JOSE_Exception("Unknown signature algorithm");
}
switch (alg)
{
case "RS256":
case "RS384":
case "RS512":
{
if (key.AsString("kty") != "RSA")
{
throw new JOSE_Exception("Wrong Key");
}
RsaDigestSigner signer = new RsaDigestSigner(digest);
RsaKeyParameters pub = new RsaKeyParameters(false, key.AsBigInteger("n"), key.AsBigInteger("e"));
signer.Init(false, pub);
signer.BlockUpdate(protectedB64, 0, protectedB64.Length);
signer.BlockUpdate(rgbDot, 0, 1);
signer.BlockUpdate(msg.payloadB64, 0, msg.payloadB64.Length);
if (!signer.VerifySignature(signature))
{
throw new JOSE_Exception("Message failed to verify");
}
}
break;
case "PS256":
case "PS384":
case "PS512":
{
PssSigner signer = new PssSigner(new RsaEngine(), digest, digest2, digest.GetDigestSize());
RsaKeyParameters pub = new RsaKeyParameters(false, key.AsBigInteger("n"), key.AsBigInteger("e"));
signer.Init(false, pub);
signer.BlockUpdate(protectedB64, 0, protectedB64.Length);
signer.BlockUpdate(rgbDot, 0, 1);
signer.BlockUpdate(msg.payloadB64, 0, msg.payloadB64.Length);
if (!signer.VerifySignature(signature))
{
throw new JOSE_Exception("Message failed to verify");
}
}
break;
case "ES256":
case "ES384":
case "ES512":
{
if (key.AsString("kty") != "EC")
{
throw new JOSE_Exception("Wrong Key Type");
}
X9ECParameters p = NistNamedCurves.GetByName(key.AsString("crv"));
ECDomainParameters parameters = new ECDomainParameters(p.Curve, p.G, p.N, p.H);
ECPoint point = p.Curve.CreatePoint(key.AsBigInteger("x"
), key.AsBigInteger("y"));
ECPublicKeyParameters pubKey = new ECPublicKeyParameters(point, parameters);
ECDsaSigner ecdsa = new ECDsaSigner();
ecdsa.Init(false, pubKey);
digest.BlockUpdate(protectedB64, 0, protectedB64.Length);
digest.BlockUpdate(rgbDot, 0, rgbDot.Length);
digest.BlockUpdate(msg.payloadB64, 0, msg.payloadB64.Length);
byte[] o1 = new byte[digest.GetDigestSize()];
digest.DoFinal(o1, 0);
BigInteger r = new BigInteger(signature, 0, signature.Length / 2);
BigInteger s = new BigInteger(signature, signature.Length / 2, signature.Length / 2);
if (!ecdsa.VerifySignature(o1, r, s))
{
throw new JOSE_Exception("Signature did not validate");
}
}
break;
case "HS256":
case "HS384":
case "HS512":
{
HMac hmac = new HMac(digest);
KeyParameter K = new KeyParameter(Message.base64urldecode(key.AsString("k")));
hmac.Init(K);
hmac.BlockUpdate(protectedB64, 0, protectedB64.Length);
hmac.BlockUpdate(rgbDot, 0, rgbDot.Length);
hmac.BlockUpdate(msg.payloadB64, 0, msg.payloadB64.Length);
byte[] resBuf = new byte[hmac.GetMacSize()];
hmac.DoFinal(resBuf, 0);
bool fVerify = true;
for (int i = 0; i < resBuf.Length; i++)
{
if (resBuf[i] != signature[i])
{
fVerify = false;
}
}
if (!fVerify)
{
throw new JOSE_Exception("Signature did not validte");
}
}
break;
case "EdDSA":
if (key.AsString("kty") != "OKP")
{
throw new JOSE_Exception("Wrong Key Type");
}
switch (key.AsString("crv"))
{
case "Ed25519":
eddsa = new COSE.EdDSA25517();
break;
default:
throw new JOSE_Exception("Unknown OKP curve");
}
COSE.EdDSAPoint eddsaPoint = eddsa.DecodePoint(key.AsBytes("x"));
byte[] toVerify = new byte[protectedB64.Length + rgbDot.Length + msg.payloadB64.Length];
Array.Copy(protectedB64, 0, toVerify, 0, protectedB64.Length);
Array.Copy(rgbDot, 0, toVerify, protectedB64.Length, rgbDot.Length);
Array.Copy(msg.payloadB64, 0, toVerify, protectedB64.Length + rgbDot.Length, msg.payloadB64.Length);
if (!eddsa.Verify(key.AsBytes("x"), toVerify, signature))
{
throw new JOSE_Exception("Signature did not validate");
}
break;
default:
throw new JOSE_Exception("Unknown algorithm");
}
}
private byte[] Sign(byte[] bytesToBeSigned)
{
string alg = null; // Get the set algorithm or infer one
try {
alg = FindAttribute("alg").AsString();
}
catch (Exception) {
;
}
if (alg == null)
{
switch (keyToSign.AsString("kty"))
{
case "RSA":
alg = "PS256";
break;
case "EC":
switch (keyToSign.AsString("crv"))
{
case "P-256":
alg = "ES256";
break;
case "P-384":
alg = "ES384";
break;
case "P-521":
alg = "ES512";
break;
default:
throw new JOSE_Exception("Unknown curve");
}
break;
default:
throw new JOSE_Exception("Unknown or unsupported key type " + keyToSign.AsString("kty"));
}
objUnprotected.Add("alg", alg);
}
IDigest digest;
IDigest digest2;
switch (alg)
{
case "RS256":
case "ES256":
case "PS256":
case "HS256":
digest = new Sha256Digest();
digest2 = new Sha256Digest();
break;
case "RS384":
case "ES384":
case "PS384":
case "HS384":
digest = new Sha384Digest();
digest2 = new Sha384Digest();
break;
case "RS512":
case "ES512":
case "PS512":
case "HS512":
digest = new Sha512Digest();
digest2 = new Sha512Digest();
break;
case "EdDSA":
digest = null;
digest2 = null;
break;
default:
throw new JOSE_Exception("Unknown signature algorithm");
}
switch (alg)
{
case "RS256":
case "RS384":
case "RS512": {
RsaDigestSigner signer = new RsaDigestSigner(digest);
RsaKeyParameters prv = new RsaPrivateCrtKeyParameters(ConvertBigNum(keyToSign.AsBytes("n")), ConvertBigNum(keyToSign.AsBytes("e")), ConvertBigNum(keyToSign.AsBytes("d")), ConvertBigNum(keyToSign.AsBytes("p")), ConvertBigNum(keyToSign.AsBytes("q")), ConvertBigNum(keyToSign.AsBytes("dp")), ConvertBigNum(keyToSign.AsBytes("dq")), ConvertBigNum(keyToSign.AsBytes("qi")));
signer.Init(true, prv);
signer.BlockUpdate(bytesToBeSigned, 0, bytesToBeSigned.Length);
return(signer.GenerateSignature());
}
case "PS256":
case "PS384":
case "PS512": {
PssSigner signer = new PssSigner(new RsaEngine(), digest, digest2, digest.GetDigestSize());
RsaKeyParameters prv = new RsaPrivateCrtKeyParameters(ConvertBigNum(keyToSign.AsBytes("n")), ConvertBigNum(keyToSign.AsBytes("e")), ConvertBigNum(keyToSign.AsBytes("d")), ConvertBigNum(keyToSign.AsBytes("p")), ConvertBigNum(keyToSign.AsBytes("q")), ConvertBigNum(keyToSign.AsBytes("dp")), ConvertBigNum(keyToSign.AsBytes("dq")), ConvertBigNum(keyToSign.AsBytes("qi")));
ParametersWithRandom rnd = new ParametersWithRandom(prv, Message.s_PRNG);
signer.Init(true, rnd);
signer.BlockUpdate(bytesToBeSigned, 0, bytesToBeSigned.Length);
return(signer.GenerateSignature());
}
case "ES256":
case "ES384":
case "ES512": {
X9ECParameters p = NistNamedCurves.GetByName(keyToSign.AsString("crv"));
ECDomainParameters parameters = new ECDomainParameters(p.Curve, p.G, p.N, p.H);
ECPrivateKeyParameters privKey = new ECPrivateKeyParameters("ECDSA", ConvertBigNum(keyToSign.AsBytes("d")), parameters);
ParametersWithRandom param = new ParametersWithRandom(privKey, Message.s_PRNG);
ECDsaSigner ecdsa = new ECDsaSigner(new HMacDsaKCalculator(new Sha256Digest()));
ecdsa.Init(true, param);
BigInteger[] sig = ecdsa.GenerateSignature(bytesToBeSigned);
byte[] r = sig[0].ToByteArray();
byte[] s = sig[1].ToByteArray();
byte[] sigs = new byte[r.Length + s.Length];
Array.Copy(r, sigs, r.Length);
Array.Copy(s, 0, sigs, r.Length, s.Length);
return(sigs);
}
case "HS256":
case "HS384":
case "HS512": {
HMac hmac = new HMac(digest);
KeyParameter key = new KeyParameter(keyToSign.AsBytes("k"));
byte[] resBuf = new byte[hmac.GetMacSize()];
hmac.Init(key);
hmac.BlockUpdate(bytesToBeSigned, 0, bytesToBeSigned.Length);
hmac.DoFinal(resBuf, 0);
return(resBuf);
}
case "EdDSA": {
switch (keyToSign.AsString("crv"))
{
case "Ed25519":
COSE.EdDSA25517 x = new COSE.EdDSA25517();
return(x.Sign(keyToSign.AsBytes("x"), keyToSign.AsBytes("d"), bytesToBeSigned));
}
}
break;
}
return(null);
}
