/// <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;
}
public override SymmetricAlgorithm DecodePrivateKey(byte[] encodedKeyExchangeData, GostKeyExchangeExportMethod keyExchangeExportMethod)
{
if (encodedKeyExchangeData == null)
{
throw ExceptionUtility.ArgumentNull("encodedKeyExchangeData");
}
int keyExchangeExportAlgId;
if (keyExchangeExportMethod == GostKeyExchangeExportMethod.GostKeyExport)
{
keyExchangeExportAlgId = Constants.CALG_SIMPLE_EXPORT;
}
else if (keyExchangeExportMethod == GostKeyExchangeExportMethod.CryptoProKeyExport)
{
keyExchangeExportAlgId = Constants.CALG_PRO_EXPORT;
}
else
{
throw ExceptionUtility.ArgumentOutOfRange("keyExchangeExportMethod");
}
var providerHandle = CryptoApiHelper.ProviderHandle;
var keyExchangeInfo = new GostKeyExchangeInfo();
keyExchangeInfo.Decode(encodedKeyExchangeData);
using (var keyHandle = CryptoApiHelper.DuplicateKey(InternalKeyHandle))
{
CryptoApiHelper.SetKeyParameterInt32(keyHandle, Constants.KP_ALGID, keyExchangeExportAlgId);
var keyExchangeHandle = CryptoApiHelper.ImportKeyExchange(providerHandle, keyExchangeInfo, keyHandle);
return new Gost28147SymmetricAlgorithm(providerHandle, keyExchangeHandle);
}
}
