/**
* Initialise the decryptor.
*
* @param publicKey the recipient's/sender's public key parameters
* @param params encoding and derivation parameters, may be wrapped to include an IV for an underlying block cipher.
* @param ephemeralKeyPairGenerator the ephemeral key pair generator to use.
*/
public void Init(AsymmetricKeyParameter publicKey, ICipherParameters @params,
EphemeralKeyPairGenerator ephemeralKeyPairGenerator)
{
ForEncryption = true;
PubParam = publicKey;
KeyPairGenerator = ephemeralKeyPairGenerator;
ExtractParams(@params);
}
public byte[] DoFinal(byte[] input, int inOff, int inLen)
{
if (inLen != 0)
{
_buffer.Write(input, inOff, inLen);
}
byte[] @in = _buffer.ToArray();
_buffer.Flush();
_buffer.SetLength(0);
// Convert parameters for use in IESEngine
ICipherParameters @params = new IesWithCipherParameters(_engineSpec.GetDerivationV(),
_engineSpec.GetEncodingV(),
_engineSpec.GetMacKeySize(),
_engineSpec.GetCipherKeySize());
if (_engineSpec.GetNonce() != null)
{
@params = new ParametersWithIV(@params, _engineSpec.GetNonce());
}
ECDomainParameters ecParams = ((ECKeyParameters)_key).Parameters;
if (_forEncryption)
{
// Generate the ephemeral key pair
ECKeyPairGenerator gen = new ECKeyPairGenerator();
gen.Init(new ECKeyGenerationParameters(ecParams, _random));
bool usePointCompression = _engineSpec.GetPointCompression();
EphemeralKeyPairGenerator
kGen = new EphemeralKeyPairGenerator(gen, new KeyEncoder(usePointCompression));
// Encrypt the buffer
try
{
_customIesEngine.Init(_key, @params, kGen);
return(_customIesEngine.ProcessBlock(@in, 0, @in.Length));
}
catch (Exception e)
{
throw new DataException("unable to process block", e);
}
}
else
{
// Decrypt the buffer
try
{
_customIesEngine.Init(_key, @params, new EciesPublicKeyParser(ecParams));
return(_customIesEngine.ProcessBlock(@in, 0, @in.Length));
}
catch (InvalidCipherTextException e)
{
throw new DataException("unable to process block", e);
}
}
}