/// <summary>
/// Дешифрует общий секретный ключ.
/// </summary>
/// <param name="encryptedKeyExchangeData">Зашифрованный общий секретный ключ.</param>
/// <exception cref="ArgumentNullException"></exception>
public SymmetricAlgorithm DecryptKeyExchangeAlgorithm(byte[] encryptedKeyExchangeData)
{
if (encryptedKeyExchangeData == null)
{
throw ExceptionUtility.ArgumentNull("encryptedKeyExchangeData");
}
var keyExchange = new GostKeyExchange();
keyExchange.Decode(encryptedKeyExchangeData);
return DecryptKeyExchangeAlgorithm(keyExchange);
}
/// <summary>
/// Шифрует общий секретный ключ.
/// </summary>
/// <param name="keyExchangeAlgorithm">Алгоритм шифрации общего секретного ключа.</param>
/// <exception cref="ArgumentNullException"></exception>
public GostKeyExchange CreateKeyExchangeInfo(SymmetricAlgorithm keyExchangeAlgorithm)
{
if (keyExchangeAlgorithm == null)
{
throw ExceptionUtility.ArgumentNull("keyExchangeAlgorithm");
}
var keyExchange = new GostKeyExchange();
var keyExchangeParameters = _publicKey.ExportParameters(false);
using (var keyExchangeAsym = new Gost3410EphemeralAsymmetricAlgorithm(keyExchangeParameters))
{
byte[] encodedKeyExchangeInfo;
using (var keyExchangeAlg = keyExchangeAsym.CreateKeyExchange(keyExchangeParameters))
{
encodedKeyExchangeInfo = keyExchangeAlg.EncodeKeyExchange(keyExchangeAlgorithm, GostKeyExchangeExportMethod.CryptoProKeyExport);
}
var keyExchangeInfo = new GostKeyExchangeInfo();
keyExchangeInfo.Decode(encodedKeyExchangeInfo);
keyExchange.SessionEncryptedKey = keyExchangeInfo;
keyExchange.TransportParameters = keyExchangeAsym.ExportParameters(false);
}
return keyExchange;
}
/// <summary>
/// Дешифрует общий секретный ключ.
/// </summary>
/// <param name="encryptedKeyExchangeInfo">Зашифрованный общий секретный ключ.</param>
/// <exception cref="ArgumentNullException"></exception>
public SymmetricAlgorithm DecryptKeyExchangeAlgorithm(GostKeyExchange encryptedKeyExchangeInfo)
{
if (encryptedKeyExchangeInfo == null)
{
throw ExceptionUtility.ArgumentNull("encryptedKeyExchangeInfo");
}
var keyExchangeAlg = _privateKey.CreateKeyExchange(encryptedKeyExchangeInfo.TransportParameters);
var encodedKeyExchangeInfo = encryptedKeyExchangeInfo.SessionEncryptedKey.Encode();
return keyExchangeAlg.DecodeKeyExchange(encodedKeyExchangeInfo, GostKeyExchangeExportMethod.CryptoProKeyExport);
}