public static Message DecodeFromJSON(CBORObject message)
{
if (message.ContainsKey("ciphertext"))
{
EncryptMessage msgx = new EncryptMessage();
msgx.InternalDecodeFromJSON(message);
return(msgx);
}
SignMessage signMessage = new SignMessage();
signMessage.InternalDecodeFromJSON(message);
return(signMessage);
}
public bool Verify(SignMessage msg)
{
string alg = FindAttribute("alg").AsString();
JWK key = keyToSign;
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 JoseException("Unknown signature algorithm");
}
//
byte[] toBeSigned;
string str = "";
string body = Encoding.UTF8.GetString(msg.payloadB64);
if (ProtectedMap.ContainsKey("b64") && ProtectedMap["b64"].AsBoolean() == false)
{
str += protectedB64 + "." + body;
}
else
{
str += protectedB64 + "." + body;
}
toBeSigned = Encoding.UTF8.GetBytes(str);
switch (alg)
{
case "RS256":
case "RS384":
case "RS512": {
if (key.AsString("kty") != "RSA")
{
throw new JoseException("Wrong Key");
}
RsaDigestSigner signer = new RsaDigestSigner(digest);
RsaKeyParameters pub = new RsaKeyParameters(false, key.AsBigInteger("n"), key.AsBigInteger("e"));
signer.Init(false, pub);
signer.BlockUpdate(toBeSigned, 0, toBeSigned.Length);
if (!signer.VerifySignature(signature))
{
throw new JoseException("Message failed to verify");
}
}
break;
case "PS256":
case "PS384":
case "PS512": {
PssSigner signer = new PssSigner(new RsaEngine(), digest, digest2, digest2.GetDigestSize());
RsaKeyParameters pub = new RsaKeyParameters(false, key.AsBigInteger("n"), key.AsBigInteger("e"));
signer.Init(false, pub);
signer.BlockUpdate(toBeSigned, 0, toBeSigned.Length);
if (!signer.VerifySignature(signature))
{
throw new JoseException("Message failed to verify");
}
}
break;
case "ES256":
case "ES384":
case "ES512": {
digest.BlockUpdate(toBeSigned, 0, toBeSigned.Length);
byte[] o1 = new byte[digest.GetDigestSize()];
digest.DoFinal(o1, 0);
if (key.AsString("kty") != "EC")
{
throw new JoseException("Wrong Key Type");
}
ICipherParameters pubKey = keyToSign.AsPublicKey();
ECDsaSigner ecdsa = new ECDsaSigner();
ecdsa.Init(false, pubKey);
BigInteger r = new BigInteger(1, signature, 0, signature.Length / 2);
BigInteger s = new BigInteger(1, signature, signature.Length / 2, signature.Length / 2);
if (!ecdsa.VerifySignature(o1, r, s))
{
throw new JoseException("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(toBeSigned, 0, toBeSigned.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 JoseException("Signature did not validate");
}
}
break;
case "EdDSA": {
ISigner eddsa;
if (key.AsString("kty") != "OKP")
{
throw new JoseException("Wrong Key Type");
}
switch (key.AsString("crv"))
{
case "Ed25519": {
Ed25519PublicKeyParameters privKey =
new Ed25519PublicKeyParameters(key.AsBytes("X"), 0);
eddsa = new Ed25519Signer();
eddsa.Init(false, privKey);
eddsa.BlockUpdate(toBeSigned, 0, toBeSigned.Length);
if (!eddsa.VerifySignature(signature))
{
throw new JoseException("Signature did not validate");
}
break;
}
default:
throw new JoseException("Unknown algorithm");
}
break;
}
default:
throw new JoseException("Unknown algorithm");
}
return(true);
}
