/// <summary>
/// Decrypt a cipher text
/// </summary>
///
/// <param name="Input">The cipher text</param>
///
/// <returns>The plain text</returns>
///
/// <exception cref="RLWEException">Thrown if cipher has not been initialized</exception>
public byte[] Decrypt(byte[] Input)
{
if (!_isInitialized)
{
throw new RLWEException("RLWEEncrypt:Decrypt", "The cipher has not been initialized!", new InvalidOperationException());
}
int plen = _N >> 3;
if (_N == 512)
{
NTT512 ntt = new NTT512(_rndEngine);
return(ntt.Decrypt((RLWEPrivateKey)_keyPair.PrivateKey, Input).SubArray(_mFp, plen - _mFp));
}
else
{
NTT256 ntt = new NTT256(_rndEngine);
return(ntt.Decrypt((RLWEPrivateKey)_keyPair.PrivateKey, Input).SubArray(_mFp, plen - _mFp));
}
}
/// <summary>
/// Decrypt a cipher text
/// </summary>
///
/// <param name="Input">The cipher text</param>
///
/// <returns>The plain text</returns>
///
/// <exception cref="CryptoAsymmetricException">Thrown if cipher has not been initialized</exception>
public byte[] Decrypt(byte[] Input)
{
if (!_isInitialized)
{
throw new CryptoAsymmetricException("RLWEEncrypt:Decrypt", "The cipher has not been initialized!", new InvalidOperationException());
}
if (_isEncryption)
{
throw new CryptoAsymmetricSignException("RLWEEncrypt:Decrypt", "The cipher is not initialized for decryption!", new ArgumentException());
}
int plen = _N >> 3;
if (_N == 512)
{
NTT512 ntt = new NTT512(_rndEngine);
return(ntt.Decrypt((RLWEPrivateKey)_asmKey, Input).SubArray(_mFp, plen - _mFp));
}
else
{
NTT256 ntt = new NTT256(_rndEngine);
return(ntt.Decrypt((RLWEPrivateKey)_asmKey, Input).SubArray(_mFp, plen - _mFp));
}
}