private static string Decrypt(Part[] parts, object key)
{
Part header = parts[0];
Part encryptedCek = parts[1];
Part iv = parts[2];
Part cipherText = parts[3];
Part authTag = parts[4];
var jwtHeader = JsonObject.Parse(header.Utf8);
var alg = jwtHeader["alg"].GetString();
var enc = jwtHeader["enc"].GetString();
if (!encryptors.ContainsKey(enc))
{
throw new Exception(string.Format("JoseRT.Jwt.Decrypt(): unknown or unsupported encryption:{0}.", enc));
}
if (!algorithms.ContainsKey(alg))
{
throw new Exception(string.Format("JoseRT.Jwt.Decrypt(): unknown or unsupported algorithm:{0}.", alg));
}
IJwaAlgorithm keys = algorithms[alg];
IJweEncryptor encryption = encryptors[enc];
byte[] cek = keys.Unwrap(encryptedCek.Bytes, key, encryption.KeySize, jwtHeader); //TODO part?
byte[] aad = Encoding.UTF8.GetBytes(Compact.Serialize(header)); //TODO: Part.New(Compact...)
byte[] plainText = encryption.Decrypt(aad, cek, iv.Bytes, cipherText.Bytes, authTag.Bytes); //TODO: all parts, return part?
return(Encoding.UTF8.GetString(plainText, 0, plainText.Length));
}
public static string Encode(string payload, string keyManagementAlg, string encryption, object key)
{
Ensure.IsNotEmpty(payload, "JoseRT.Jwt.Encode(): payload expected to be not empty, whitespace or null.");
if (!encryptors.ContainsKey(encryption))
{
throw new Exception(string.Format("JoseRT.Jwt.Encode(): unknown or unsupported encryption algorithm:{0}.", encryption));
}
if (!algorithms.ContainsKey(keyManagementAlg))
{
throw new Exception(string.Format("JoseRT.Jwt.Encode(): unknown or unsupported key management algorithm:{0}.", keyManagementAlg));
}
IJweEncryptor encryptor = encryptors[encryption];
IJwaAlgorithm algorithm = algorithms[keyManagementAlg];
var jwtHeader = new JsonObject
{
{ "enc", JsonValue.CreateStringValue(encryption) },
{ "alg", JsonValue.CreateStringValue(keyManagementAlg) }
};
Part[] keys = algorithm.WrapNewKey(encryptor.KeySize, key, jwtHeader);
Part cek = keys[0];
Part encryptedCek = keys[1];
Part header = Part.New(jwtHeader.Stringify());
byte[] plainText = Encoding.UTF8.GetBytes(payload);
byte[] aad = Encoding.UTF8.GetBytes(Compact.Serialize(header));
Part[] encParts = encryptor.Encrypt(aad, plainText, cek.Bytes);
return(Compact.Serialize(header, encryptedCek, encParts[0], encParts[1], encParts[2]));
}
public static void RegisterJwa(IJwaAlgorithm algorithm)
{
algorithms[algorithm.Name] = algorithm;
}