/// <summary>
/// CFB decode.
/// </summary>
/// <param name="key">Key</param>
/// <param name="iv">Init vector</param>
/// <param name="message">Message</param>
/// <param name="sBlockType">SBlock type</param>
/// <returns>Decoded</returns>
public static byte[] Decode(byte[] key, byte[] iv, byte[] message, SBlockTypes sBlockType)
{
CheckData(key, iv, message);
using var gost = new GostManager(key, iv, message, CipherTypes.Cfb, sBlockType);
return(gost.Decode());
}
/// <summary>
/// Simple substitution encode.
/// </summary>
/// <param name="key">256 bit key.</param>
/// <param name="message">Opened message</param>
/// <param name="sBlockType">STable.</param>
/// <returns>Encoded message.</returns>
//
//Если входящее сообщение не кратно 8 байтам, то дополняем его
//в каждый свободный бит после расширения блока дописываем значение равное количеству байтов которые мы добавили
public byte[] SimpleSubstitutionEncode(byte[] key, byte[] message, SBlockTypes sBlockType = SBlockTypes.GOST)
{
Key = key;
//расширение и дописываний байтов
if (message.Length % 8 != 0)
{
int offset = 8 - (message.Length - (message.Length / 8) * 8);
byte[] newarray = new byte[(message.Length / 8) * 8 + 8];
Array.Copy(message, newarray, message.Length);
for (int i = message.Length; i < newarray.Length; i++)
{
newarray[i] = (byte)offset;
}
Message = newarray;
}
else
{
SubstitutionEncode(key, message, sBlockType);
}
this.sBlockType = sBlockType;
SetSBlock();
byte[] encode = SubstitutionProcess(true);
return(encode);
}
/// <summary>
/// Substitution decode.
/// </summary>
/// <param name="key">Key</param>
/// <param name="message">Message</param>
/// <param name="sBlockType">SBlock type</param>
/// <returns>Decoded</returns>
public static byte[] Decode(string key, string message, SBlockTypes sBlockType)
{
CheckData(key, message);
var byteKey = Encoding.Default.GetBytes(key);
var byteMessage = Encoding.Default.GetBytes(message);
return(Decode(byteKey, byteMessage, sBlockType));
}
/// <summary>
/// MAC generator.
/// </summary>
/// <param name="key">256 bit key.</param>
/// <param name="message">Message (not less than 2 blocks).</param>
/// <param name="sBlockType">SBlock.</param>
/// <returns>MAC.</returns>
public byte[] MACGenerator(byte[] key, byte[] message, SBlockTypes sBlockType = SBlockTypes.GOST)
{
Key = key;
Message = message;
this.sBlockType = sBlockType;
SetSBlock();
byte[] mac = MACProcess();
return(mac);
}
public static ISBlock SBlock(SBlockTypes sBlock)
{
return(sBlock switch
{
SBlockTypes.CryptoProA => new CryptoProABlock(),
SBlockTypes.CryptoProB => new CryptoProBBlock(),
SBlockTypes.CryptoProC => new CryptoProCBlock(),
SBlockTypes.CryptoProD => new CryptoProDBlock(),
SBlockTypes.TC26 => new Tc26Block(),
SBlockTypes.GOST => new GostBlock(),
_ => throw new ArgumentException(nameof(sBlock)),
});
/// <summary>
/// CFB decode.
/// </summary>
/// <param name="key">256 bit key.</param>
/// <param name="iv">64 bit IV</param>
/// <param name="message">Encoded message.</param>
/// <param name="sBlockType">STable.</param>
/// <returns>Opened message.</returns>
/// <exception cref="Exception"></exception>
/// <exception cref="ArgumentException"></exception>
public byte[] CFBDecode(byte[] key, byte[] iv, byte[] message, SBlockTypes sBlockType = SBlockTypes.GOST)
{
Key = key;
Message = message;
IV = iv;
this.sBlockType = sBlockType;
SetSBlock();
byte[] encode = CFBProcess(false);
return(encode);
}
/// <summary>
/// Substitution decode.
/// </summary>
/// <param name="key">Key</param>
/// <param name="message">Message</param>
/// <param name="sBlockType">SBlock type</param>
/// <returns>Decoded</returns>
public static byte[] Decode(byte[] key, byte[] message, SBlockTypes sBlockType)
{
CheckData(key, message);
if (message.Length % 8 != 0)
{
throw new ArgumentException("Block must have 64 bit length");
}
using var gost = new GostManager(key, null, message, CipherTypes.Substitution, sBlockType);
return(gost.Decode());
}
/// <summary>
/// Substitution decode.
/// </summary>
/// <param name="key">256 bit key.</param>
/// <param name="message">Encoded message multiple of 64 bit.</param>
/// <param name="sBlockType">STable.</param>
/// <returns>Opened message</returns>
/// <exception cref="Exception"></exception>
/// <exception cref="ArgumentException"></exception>
public byte[] SubstitutionDecode(byte[] key, byte[] message, SBlockTypes sBlockType = SBlockTypes.GOST)
{
Key = key;
Message = message;
if (message.Length % 8 != 0)
{
throw new ArgumentException("Block must have 64 bit length");
}
this.sBlockType = sBlockType;
SetSBlock();
byte[] decode = SubstitutionProcess(false);
return(decode);
}
public GostManager(byte[] key, byte[] iv, byte[] message, CipherTypes cipherType = CipherTypes.Substitution,
SBlockTypes sBlockType = SBlockTypes.GOST)
{
released = false;
_subKeys = new List <uint>();
Key = key;
IV = iv;
Message = message;
GenerateSubKeys();
_sBlock = SBlockFactory.SBlock(sBlockType);
_cipher = CipherFactory.Cipher(_iv, _subKeys, cipherType, _sBlock);
}
/// <summary>
/// Simple substitution decode.
/// </summary>
/// <param name="key">256 bit key.</param>
/// <param name="message">Opened message</param>
/// <param name="sBlockType">STable.</param>
/// <returns>Decoded message.</returns>
//
//После расшифровки текста берем количество добавленные байт и обрезаем блок
public byte[] SimpleSubstitutionDecode(byte[] key, byte[] message, SBlockTypes sBlockType = SBlockTypes.GOST)
{
Key = key;
Message = message;
this.sBlockType = sBlockType;
SetSBlock();
byte[] encode = SubstitutionProcess(false);
int offset = encode[encode.Length - 1];
byte[] array = new byte[encode.Length - offset];
for (int i = 0; i < array.Length; i++)
{
array[i] = encode[i];
}
encode = array;
return(encode);
}
/// <summary>
/// XOR decode.
/// </summary>
/// <param name="key">256 bit key.</param>
/// <param name="iv">64 bit IV</param>
/// <param name="message">Encoded message.</param>
/// <param name="sBlockType">STable.</param>
/// <returns>Opened message.</returns>
/// <exception cref="Exception"></exception>
/// <exception cref="ArgumentException"></exception>
public byte[] XORDecode(byte[] key, byte[] iv, byte[] message, SBlockTypes sBlockType = SBlockTypes.GOST)
{
return(XOREncode(key, iv, message, sBlockType));;
}
