public static MatrixInt Decrypt(ILinearCode linearCode, IList <int> permutation, IList <int> mask, MatrixInt scramblerMatrix, ParityCheckMatrixGeneratorEllyptic generator, MatrixInt encryptedMessage)
{
var message = encryptedMessage.Clone();
#region Unmask
for (int col = 0; col < message.ColumnCount; col++)
{
for (int row = 0; row < message.RowCount; row++)
{
message[row, col] = linearCode.GaloisField.MultiplyWords(message[row, col], linearCode.GaloisField.GetMultiplicativeInverse(mask[col]));
}
}
#endregion
Debug.WriteLine(message);
#region Inverse permutation
var inversePermutation = Helper.InversePermutation(permutation);
message = message.PermuteColumns(inversePermutation);
#endregion
Debug.WriteLine(message);
#region Correct Errors
var correctedMessage = DecoderEllyptic.DecodeAndCorrect(linearCode, message, generator);
#endregion
Debug.WriteLine(correctedMessage);
#region Apply the inverse scrambler matrix
var inverseScramblerMatrix = MatrixAlgorithms.MatrixInverse(scramblerMatrix, linearCode.GaloisField);
var decryptedMessage = MatrixAlgorithms.DotMultiplication(correctedMessage, inverseScramblerMatrix, linearCode.GaloisField);
#endregion
return(decryptedMessage);
}
public MatrixInt DecryptMessage(MatrixInt encryptedMessage)
{
var message = encryptedMessage.Clone();
#region Unmask
for (int col = 0; col < message.ColumnCount; col++)
{
for (int row = 0; row < message.RowCount; row++)
{
message[row, col] = LinearCode.GaloisField.MultiplyWords(message[row, col], PrivateKey.InverseMask[col]);
}
}
#endregion
Debug.WriteLine(message);
#region Inverse permutation
message = message.PermuteColumns(PrivateKey.InversePermutation);
#endregion
Debug.WriteLine(message);
#region Correct Errors
var correctedMessage = DecoderEllyptic.DecodeAndCorrect(LinearCode, message, _generator);
#endregion
Debug.WriteLine(correctedMessage);
#region Apply the inverse scrambler matrix
var decryptedMessage = MatrixAlgorithms.DotMultiplication(correctedMessage, PrivateKey.InverseScramblerMatrix, LinearCode.GaloisField);
#endregion
return(decryptedMessage);
}
