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);
}
private void btnDecrypt_Click(object sender, EventArgs e)
{
try
{
EncryptedAsymmetric encrypted = Newtonsoft.Json.JsonConvert.DeserializeObject <EncryptedAsymmetric>(txtCryptText.Text);
txtClearText.Text = CryptHandler.Decrypt(txtPrivateKey.Text, txtPublicKeyPartner.Text, encrypted);
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
public static EncryptedAsymmetric Encrypt(string xmlPrivateKey, string xmlPublicKey, string message)
{
EncryptedAsymmetric output = new EncryptedAsymmetric();
var symmetric = EncryptSymmetric(message);
output.SymmetricData = symmetric.Encrypted;
output.SymmetricName = symmetric.Name;
output.SymmetricIVLength = symmetric.IV.Length;
output.SymmetricKeyLength = symmetric.Key.Length;
var hashed = Hash(CryptHandler.Encoding.GetBytes(message));
//output.HashData = hashed.Data;
output.HashName = hashed.Name;
output.HashLength = hashed.Data.Length;
using (var cryptAlgorithm = CryptHandler.CreateAsymmetric(xmlPrivateKey))
{
// Sign with PrivateKey, so the receiver can make sure that the sender
// is correct, because only sender PublicKey will be able to verify signature.
List <byte> dataToSign = new List <byte>();
dataToSign.AddRange(symmetric.IV);
dataToSign.AddRange(symmetric.Key);
dataToSign.AddRange(hashed.Data);
//output.AsymmetricSignature = cryptAlgorithm.SignHash(output.HashData, new HashAlgorithmName(hashed.Name), padding);
output.AsymmetricSignature = cryptAlgorithm.SignData(dataToSign.ToArray(), new HashAlgorithmName(hashed.Name), padding);
//output.AsymmetricSignatureLength = output.AsymmetricSignature.Length;
}
using (var cryptAlgorithm = CryptHandler.CreateAsymmetric(xmlPublicKey))
{
// Encrypt with receiver PublicKey, so only receiver PrivateKey will
// be able to decrypt it.
List <byte> dataToEncrypt = new List <byte>();
dataToEncrypt.AddRange(symmetric.IV);
dataToEncrypt.AddRange(symmetric.Key);
dataToEncrypt.AddRange(hashed.Data);
//dataToEncrypt.AddRange(output.AsymmetricSignature);
output.AsymmetricData = cryptAlgorithm.Encrypt(dataToEncrypt.ToArray(), RSAEncryptionPadding.OaepSHA256);
output.AsymmetricName = cryptAlgorithm.GetType().BaseType.Name;
}
return(output);
}
