/// <summary>
/// Encrypt file with IDEA encryption
/// </summary>
public void Encrypt()
{
GenerateKeys();
var md5 = MD5.Create().ComputeHash(SrcFileStream);
CreateKeyFile(md5);
//запись MD5 хеша в зашифрованный файл
ResFileStream.Write(md5, 0, md5.Length);
//шифрование файла
SrcFileStream.Seek(0, SeekOrigin.Begin);
ResFileStream.WriteByte((byte)(8 - (SrcFileStream.Length % 8)));
for (long i = 0; i < SrcFileStream.Length; i += 8)
{
EncryptionRounds();
}
ResFileStream.Flush();
}
/// <summary>
/// Decrypt the file encrypted IDEA encryption
/// </summary>
/// <param name="SrcFileStream">Input file stream of the encrypted file</param>
/// <param name="ResFileStream">Output file stream of the decrypted file</param>
/// <param name="KeyFileStream">Input file stream of the key file</param>
public void Decrypt()
{
GenerateKey();
SrcFileStream.Seek(17, SeekOrigin.Begin);
ResFileStream.Seek(0, SeekOrigin.Begin);
for (long i = 17; i < SrcFileStream.Length; i += 8)
{
DecryptionRounds();
}
SrcFileStream.Seek(16, SeekOrigin.Begin);
byte offset = (byte)SrcFileStream.ReadByte();
if (!(offset == 8))
{
ResFileStream.SetLength(ResFileStream.Length - SrcFileStream.ReadByte());
}
ResFileStream.Flush();
}
