private static EncryptedSymmetric EncryptSymmetric(string message)
{
EncryptedSymmetric encrypted;
using (var symmetric = CryptHandler.CreateSymmetric())
{
symmetric.GenerateIV();
symmetric.GenerateKey();
using (var ms = new System.IO.MemoryStream())
{
using (var cs = new CryptoStream(ms, symmetric.CreateEncryptor(), CryptoStreamMode.Write))
{
using (var writer = new StreamWriter(cs, CryptHandler.Encoding))
{
writer.Write(message);
}
}
encrypted = new EncryptedSymmetric()
{
Name = symmetric.GetType().BaseType.Name,
IV = symmetric.IV,
Key = symmetric.Key,
Encrypted = ms.ToArray()
};
}
symmetric.Clear();
}
return(encrypted);
}
public static string Decrypt(string xmlPivateKey, string xmlPublicKey, EncryptedAsymmetric input)
{
EncryptedSymmetric symmetric = new EncryptedSymmetric()
{
Name = input.SymmetricName,
IV = new byte[input.SymmetricIVLength],
Key = new byte[input.SymmetricKeyLength]
};
Hashed hashed = new Hashed()
{
Name = input.HashName,
Data = new byte[input.HashLength]
};
byte[] asymmetricDataDecrypted;
using (var cryptAlgorithm = CryptHandler.CreateAsymmetric(xmlPivateKey))
{
asymmetricDataDecrypted = cryptAlgorithm.Decrypt(input.AsymmetricData, RSAEncryptionPadding.OaepSHA256);
}
int sourceStartPosition = 0;
Array.Copy(asymmetricDataDecrypted, sourceStartPosition, symmetric.IV, 0, input.SymmetricIVLength);
sourceStartPosition += input.SymmetricIVLength;
Array.Copy(asymmetricDataDecrypted, sourceStartPosition, symmetric.Key, 0, input.SymmetricKeyLength);
sourceStartPosition += input.SymmetricKeyLength;
Array.Copy(asymmetricDataDecrypted, sourceStartPosition, hashed.Data, 0, input.HashLength);
using (var cryptAlgorithm = CryptHandler.CreateAsymmetric(xmlPublicKey))
{
//byte[] dataToVerify = new byte[input.SymmetricIVLength + input.SymmetricKeyLength + input.HashLength];
//Array.Copy(asymmetricDataDecrypted, 0, dataToVerify, 0, dataToVerify.Length);
bool isDataVerified = cryptAlgorithm.VerifyData(asymmetricDataDecrypted, input.AsymmetricSignature, new HashAlgorithmName(input.HashName), padding);
if (!isDataVerified)
{
throw new Exception("Crypt data can't be verified.");
}
//bool isHashVerified = cryptAlgorithm.VerifyHash(hashed.Data, input.AsymmetricSignature, new HashAlgorithmName(input.HashName), padding);
//if (!isHashVerified)
//{
// throw new Exception("Crypt hash can't be verified.");
//}
}
var symmetricDataDecrypted = DecryptSymmetric(input.SymmetricData, symmetric.IV, symmetric.Key);
var hashedToCompare = Hash(CryptHandler.Encoding.GetBytes(symmetricDataDecrypted));
var isHashVerified = hashedToCompare.Data.SequenceEqual(hashed.Data);
if (!isHashVerified)
{
throw new Exception("Hash can't be verified.");
}
return(symmetricDataDecrypted);
}