/// <summary>
/// Encrypt a plain text message
/// </summary>
///
/// <param name="Input">The plain text</param>
///
/// <returns>The cipher text</returns>
///
/// <exception cref="CryptoAsymmetricException">Thrown if cipher has not been initialized, or input text is too long</exception>
public byte[] Encrypt(byte[] Input)
{
if (!_isInitialized)
throw new CryptoAsymmetricException("RLWEEncrypt:Encrypt", "The cipher has not been initialized!", new InvalidOperationException());
if (Input.Length > _maxPlainText - _mFp)
throw new CryptoAsymmetricException("RLWEEncrypt:Encrypt", "The input text is too long!", new ArgumentOutOfRangeException());
if (!_isEncryption)
throw new CryptoAsymmetricException("RLWEEncrypt:Encrypt", "The cipher is not initialized for encryption!", new ArgumentException());
int plen = _N >> 3;
if (_N == 512)
{
NTT512 ntt = new NTT512(_rndEngine);
byte[] ptx = new byte[plen];
if (Input.Length < _maxPlainText)
{
ptx = _rndEngine.GetBytes(plen);
Array.Copy(Input, 0, ptx, _mFp, Input.Length);
}
else
{
Array.Copy(Input, 0, ptx, 0, Input.Length);
}
return ntt.Encrypt((RLWEPublicKey)_asmKey, ptx);
}
else
{
NTT256 ntt = new NTT256(_rndEngine);
byte[] ptx = new byte[plen];
if (Input.Length < _maxPlainText)
{
ptx = _rndEngine.GetBytes(plen);
Array.Copy(Input, 0, ptx, _mFp, Input.Length);
}
else
{
Array.Copy(Input, 0, ptx, 0, Input.Length);
}
return ntt.Encrypt((RLWEPublicKey)_asmKey, ptx);
}
}
/// <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 CryptoAsymmetricException("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);
}
}
