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Old October 20th, 2007, 07:15 PM
F3553 F3553 is offline
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Default Strange problem...

Greetings to all programming folks out there! ;)

I have a problem. When I try to use the data_decrypt function (described below), and when the data to be decrypted is larger then 14b, it don´t work.
The Data[0] gives a wrong value after the decrypt stage. I have no idea why this happens. I would be thankful if someone could help me.

(You can use the aes.h code freely but give credit where credit is due)

test.cpp
Code:
#include <iostream>
#include "aes.h"
using namespace std;
int main()
{
    int key[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
    int ekey[176];
    KeySchedule(key, 128, ekey);
    char data[16+15] = "ABCDEFGHIJKLMNOP";
    int lenght = 16;

    //for(int i = 0; i < lenght; i++)
    //   cout << data[i] << " ";
    //cout << endl  << endl;

    data_encrypt(data, lenght, ekey, 128);
    cout << endl;
    //for(int i = 0; i < lenght+15; i++)
    //   cout << data[i] << " ";
    //cout << endl  << endl;

    data_decrypt(data, lenght+15, ekey, 128);

    //for(int i = 0; i < lenght; i++)
    //   cout << data[i] << " ";
    //cout << endl  << endl;

    system("pause");
    return 0;
}

aes.h
Code:
//By: Mattias Festin
//E-mail: [email protected]
//Website: http://www.tesseract-code.se
using namespace std;
int KeySchedule(int *key,  int bit, int *keye);
int AddRoundKey(int *a, int *subkey);
int SubBytes(int *a,  bool inv);
int ShiftRows(int *a, int bit, bool inv);
int MixColumns(int *a, bool inv);

int Round(int *a, int *subkey, bool inv, int bit);
int encrypt(int *data, int *keye, int bit);
int decrypt(int *data, int *keye, int bit);

int data_encrypt(char *buf, int lenght, int *ekey, int bit);
int data_decrypt(char *buf, int lenght, int *ekey, int bit);

int BitRotate(int *a);

int mix_c(int *a, bool inv);
int gmul(int a, int b);
int gf_m(int a, int b);

int vlog[256] = {
0x00, 0xff, 0xc8, 0x08, 0x91, 0x10, 0xd0, 0x36, 
0x5a, 0x3e, 0xd8, 0x43, 0x99, 0x77, 0xfe, 0x18, 
0x23, 0x20, 0x07, 0x70, 0xa1, 0x6c, 0x0c, 0x7f, 
0x62, 0x8b, 0x40, 0x46, 0xc7, 0x4b, 0xe0, 0x0e, 
0xeb, 0x16, 0xe8, 0xad, 0xcf, 0xcd, 0x39, 0x53, 
0x6a, 0x27, 0x35, 0x93, 0xd4, 0x4e, 0x48, 0xc3, 
0x2b, 0x79, 0x54, 0x28, 0x09, 0x78, 0x0f, 0x21, 
0x90, 0x87, 0x14, 0x2a, 0xa9, 0x9c, 0xd6, 0x74, 
0xb4, 0x7c, 0xde, 0xed, 0xb1, 0x86, 0x76, 0xa4, 
0x98, 0xe2, 0x96, 0x8f, 0x02, 0x32, 0x1c, 0xc1, 
0x33, 0xee, 0xef, 0x81, 0xfd, 0x30, 0x5c, 0x13, 
0x9d, 0x29, 0x17, 0xc4, 0x11, 0x44, 0x8c, 0x80, 
0xf3, 0x73, 0x42, 0x1e, 0x1d, 0xb5, 0xf0, 0x12, 
0xd1, 0x5b, 0x41, 0xa2, 0xd7, 0x2c, 0xe9, 0xd5, 
0x59, 0xcb, 0x50, 0xa8, 0xdc, 0xfc, 0xf2, 0x56, 
0x72, 0xa6, 0x65, 0x2f, 0x9f, 0x9b, 0x3d, 0xba, 
0x7d, 0xc2, 0x45, 0x82, 0xa7, 0x57, 0xb6, 0xa3, 
0x7a, 0x75, 0x4f, 0xae, 0x3f, 0x37, 0x6d, 0x47, 
0x61, 0xbe, 0xab, 0xd3, 0x5f, 0xb0, 0x58, 0xaf, 
0xca, 0x5e, 0xfa, 0x85, 0xe4, 0x4d, 0x8a, 0x05, 
0xfb, 0x60, 0xb7, 0x7b, 0xb8, 0x26, 0x4a, 0x67, 
0xc6, 0x1a, 0xf8, 0x69, 0x25, 0xb3, 0xdb, 0xbd, 
0x66, 0xdd, 0xf1, 0xd2, 0xdf, 0x03, 0x8d, 0x34, 
0xd9, 0x92, 0x0d, 0x63, 0x55, 0xaa, 0x49, 0xec, 
0xbc, 0x95, 0x3c, 0x84, 0x0b, 0xf5, 0xe6, 0xe7, 
0xe5, 0xac, 0x7e, 0x6e, 0xb9, 0xf9, 0xda, 0x8e, 
0x9a, 0xc9, 0x24, 0xe1, 0x0a, 0x15, 0x6b, 0x3a, 
0xa0, 0x51, 0xf4, 0xea, 0xb2, 0x97, 0x9e, 0x5d, 
0x22, 0x88, 0x94, 0xce, 0x19, 0x01, 0x71, 0x4c, 
0xa5, 0xe3, 0xc5, 0x31, 0xbb, 0xcc, 0x1f, 0x2d, 
0x3b, 0x52, 0x6f, 0xf6, 0x2e, 0x89, 0xf7, 0xc0, 
0x68, 0x1b, 0x64, 0x04, 0x06, 0xbf, 0x83, 0x38};

int alog[256] = {
0x01, 0xe5, 0x4c, 0xb5, 0xfb, 0x9f, 0xfc, 0x12, 
0x03, 0x34, 0xd4, 0xc4, 0x16, 0xba, 0x1f, 0x36, 
0x05, 0x5c, 0x67, 0x57, 0x3a, 0xd5, 0x21, 0x5a, 
0x0f, 0xe4, 0xa9, 0xf9, 0x4e, 0x64, 0x63, 0xee, 
0x11, 0x37, 0xe0, 0x10, 0xd2, 0xac, 0xa5, 0x29, 
0x33, 0x59, 0x3b, 0x30, 0x6d, 0xef, 0xf4, 0x7b, 
0x55, 0xeb, 0x4d, 0x50, 0xb7, 0x2a, 0x07, 0x8d, 
0xff, 0x26, 0xd7, 0xf0, 0xc2, 0x7e, 0x09, 0x8c, 
0x1a, 0x6a, 0x62, 0x0b, 0x5d, 0x82, 0x1b, 0x8f, 
0x2e, 0xbe, 0xa6, 0x1d, 0xe7, 0x9d, 0x2d, 0x8a, 
0x72, 0xd9, 0xf1, 0x27, 0x32, 0xbc, 0x77, 0x85, 
0x96, 0x70, 0x08, 0x69, 0x56, 0xdf, 0x99, 0x94, 
0xa1, 0x90, 0x18, 0xbb, 0xfa, 0x7a, 0xb0, 0xa7, 
0xf8, 0xab, 0x28, 0xd6, 0x15, 0x8e, 0xcb, 0xf2, 
0x13, 0xe6, 0x78, 0x61, 0x3f, 0x89, 0x46, 0x0d, 
0x35, 0x31, 0x88, 0xa3, 0x41, 0x80, 0xca, 0x17, 
0x5f, 0x53, 0x83, 0xfe, 0xc3, 0x9b, 0x45, 0x39, 
0xe1, 0xf5, 0x9e, 0x19, 0x5e, 0xb6, 0xcf, 0x4b, 
0x38, 0x04, 0xb9, 0x2b, 0xe2, 0xc1, 0x4a, 0xdd, 
0x48, 0x0c, 0xd0, 0x7d, 0x3d, 0x58, 0xde, 0x7c, 
0xd8, 0x14, 0x6b, 0x87, 0x47, 0xe8, 0x79, 0x84, 
0x73, 0x3c, 0xbd, 0x92, 0xc9, 0x23, 0x8b, 0x97, 
0x95, 0x44, 0xdc, 0xad, 0x40, 0x65, 0x86, 0xa2, 
0xa4, 0xcc, 0x7f, 0xec, 0xc0, 0xaf, 0x91, 0xfd, 
0xf7, 0x4f, 0x81, 0x2f, 0x5b, 0xea, 0xa8, 0x1c, 
0x02, 0xd1, 0x98, 0x71, 0xed, 0x25, 0xe3, 0x24, 
0x06, 0x68, 0xb3, 0x93, 0x2c, 0x6f, 0x3e, 0x6c, 
0x0a, 0xb8, 0xce, 0xae, 0x74, 0xb1, 0x42, 0xb4, 
0x1e, 0xd3, 0x49, 0xe9, 0x9c, 0xc8, 0xc6, 0xc7, 
0x22, 0x6e, 0xdb, 0x20, 0xbf, 0x43, 0x51, 0x52, 
0x66, 0xb2, 0x76, 0x60, 0xda, 0xc5, 0xf3, 0xf6, 
0xaa, 0xcd, 0x9a, 0xa0, 0x75, 0x54, 0x0e, 0x01};


int Rcon[255] = {0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb};

int a_sbox[256] =   {
    //0     1    2      3     4    5     6     7      8    9     A      B    C     D     E     F
    0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, //0
    0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, //1
    0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, //2
    0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, //3
    0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, //4
    0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, //5
    0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, //6
    0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, //7
    0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, //8
    0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, //9
    0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, //A
    0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, //B
    0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, //C
    0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, //D
    0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, //E
    0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d }; //F

int sbox[256] =   {
    //0     1    2      3     4    5     6     7      8    9     A      B    C     D     E     F
    0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, //0
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, //1
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, //2
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, //3
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, //4
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, //5
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, //6
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, //7
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, //8
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, //9
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, //A
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, //B
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, //C
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, //D
    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, //E
    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 }; //F


int Round(int *a, int *subkey, bool inv, int bit)
{
    if(inv == false)
    {
       AddRoundKey(a, subkey);
       SubBytes(a, inv);
       ShiftRows(a, bit, inv);
       MixColumns(a, inv);
    }
    if(inv == true)
    {
       MixColumns(a, inv);
       ShiftRows(a, bit, inv);
       SubBytes(a, inv);
       AddRoundKey(a, subkey);
    }
}

int encrypt(int *data, int *ekey, int bit)
{
    int c;
    if(bit == 128)
       c = 176;
    else
    {
        if(bit == 196)
           c = 208;
        else
           c = 240;
    }
    int  subkey[16], subkey2[16];

    for(int j = 0; j < c/16-2; j++)
    {
    for(int i = 0; i < 16; i++)
       subkey[i] = ekey[i+j*16];
    Round(data, subkey, false, bit);
    }
    for(int i = 0; i < 16; i++)
    {
       subkey[i] = ekey[i+c-33];
       subkey2[i] = ekey[i+c-17];
    }
    AddRoundKey(data, subkey);
    SubBytes(data, false);
    ShiftRows(data, bit, false);
    AddRoundKey(data, subkey2);
}

int decrypt(int *data, int *ekey, int bit)
{
    int c;
    if(bit == 128)
       c = 176;
    else
    {
        if(bit == 196)
           c = 208;
        else
           c = 240;
    }
    int subkey[16], subkey2[16];

    for(int i = 0; i < 16; i++)
    {
       subkey[i] = ekey[i+c-33];
       subkey2[i] = ekey[i+c-17];
    }

    AddRoundKey(data, subkey2);
    ShiftRows(data, bit, true);
    SubBytes(data, true);
    AddRoundKey(data, subkey);
    for(int j = c/16-3; j > -1; j--)
    {
    for(int i = 0; i < 16; i++)
       subkey[i] = ekey[i+j*16];
    Round(data, subkey, true, bit);
    }
}

//----------------------------------------------
int AddRoundKey(int *a, int *subkey)
{
    for(int i = 0; i < 16; i++)
       a[i] ^= subkey[i];
    return 0;
}

int KeySchedule(int *key,  int bit, int *keye)
{
    int c;
    int b;
    int t[4];
    int i = 1;

    if(bit == 128)
    {
       c = 16;
       b = 176;
       i = 1;
    }
    else
    {
       if(bit == 192)
       {
          c = 24;
          b = 208;
          i = 1;
       }
       else
       {
          c = 32;
          b = 240;
          i = 1;
       }    
    }
    int n = c;

    int ut[b];
    for(int j = 0; j < c; j++)
    {
       ut[j] = *key;
       key++;

       if(c-j < 4)
          t[c-j] = ut[j];
    }

       while(c < b)
       {
          for(int j = 0; j < 4; j++) 
             t[j] = ut[j + c - 4];
          if(c % n == 0)
          {
            BitRotate(t);
            for(int j = 0; j < 4; j++) 
                t[j] = sbox[t[j]];
            t[0] ^= Rcon[i];
            i++;
          }
          if(bit == 256)
          {
             if(c % 32 == 16)
             {
                for(int j = 0; j < 4; j++) 
                   t[j] = sbox[t[j]];
             }
          }
          for(int j = 0; j < 4; j++)
          {
             ut[c] = ut[c - n] ^ t[j];
             c++;
          }
        }

    for(int j = 0; j < b; j++)
    {
       keye[j] = ut[j];
    }
    return 0;
}


int SubBytes(int *a, bool inv)
{
    if(inv)
       for(int i = 0; i < 16; i++)
          a[i] = a_sbox[a[i]];
    else

       for(int i = 0; i < 16; i++)
          a[i] = sbox[a[i]];

    return 1;
}



int MixColumns(int *a, bool inv)
{  
    for(int j = 0; j < 4; j++)
    {
       int xb[4];
       for(int i = 0; i < 4; i++)
       {
          xb[i] = a[i*4+j];
       }
       mix_c(xb, inv);
       for(int i = 0; i < 4; i++)
       {
          a[i*4+j] = xb[i];
       }
    }
    return 1;
}

int ShiftRows(int *a, int bit, bool inv)
{
    int times;
    if(bit == 128)
    {
       times = 16;
    }
    else
    {
        if(bit == 192)
        {
           times = 24;
        }
        else
           times = 32;
    }

    int xb[times];
    for(int i = 0; i < times; i++)
       xb[i] = a[i];

    if(inv)
    {
    if(bit == 128)
    {
       a[5] = xb[4];
       a[6] = xb[5];
       a[7] = xb[6];
       a[4] = xb[7];

       a[10] = xb[8];
       a[11] = xb[9];
       a[8] = xb[10];
       a[9] = xb[11];

       a[15] = xb[12];
       a[12] = xb[13];
       a[13] = xb[14];
       a[14] = xb[15];
    }

    if(bit == 192)
    {
       a[7] = xb[6];
       a[8] = xb[7];
       a[9] = xb[8];
       a[10] = xb[9];
       a[11] = xb[10];
       a[6] = xb[11];

       a[14] = xb[12];
       a[15] = xb[13];
       a[16] = xb[14];
       a[17] = xb[15];
       a[12] = xb[16];
       a[13] = xb[17];

       a[21] = xb[18];
       a[22] = xb[19];
       a[23] = xb[20];
       a[18] = xb[21];
       a[19] = xb[22];
       a[20] = xb[23];
    }

    if(bit == 256)
    {
       a[9] = xb[8];
       a[10] = xb[9];
       a[11] = xb[10];
       a[12] = xb[11];
       a[13] = xb[12];
       a[14] = xb[13];
       a[15] = xb[14];
       a[8] = xb[15];


       a[19] = xb[16];
       a[20] = xb[17];
       a[21] = xb[18];
       a[22] = xb[19];
       a[23] = xb[20];
       a[16] = xb[21];
       a[17] = xb[22];
       a[18] = xb[23];

       a[28] = xb[24];
       a[29] = xb[25];
       a[30] = xb[26];
       a[31] = xb[27];
       a[24] = xb[28];
       a[25] = xb[29];
       a[26] = xb[30];
       a[27] = xb[31];
    }
    }
    else
    {
    if(bit == 128)
    {
       a[4] = xb[5];
       a[5] = xb[6];
       a[6] = xb[7];
       a[7] = xb[4];

       a[8] = xb[10];
       a[9] = xb[11];
       a[10] = xb[8];
       a[11] = xb[9];

       a[12] = xb[15];
       a[13] = xb[12];
       a[14] = xb[13];
       a[15] = xb[14];
    }

    if(bit == 192)
    {
       a[6] = xb[7];
       a[7] = xb[8];
       a[8] = xb[9];
       a[9] = xb[10];
       a[10] = xb[11];
       a[11] = xb[6];

       a[12] = xb[14];
       a[13] = xb[15];
       a[14] = xb[16];
       a[15] = xb[17];
       a[16] = xb[12];
       a[17] = xb[13];

       a[18] = xb[21];
       a[19] = xb[22];
       a[20] = xb[23];
       a[21] = xb[18];
       a[22] = xb[19];
       a[23] = xb[20];
    }

    if(bit == 256)
    {
       a[8] = xb[9];
       a[9] = xb[10];
       a[10] = xb[11];
       a[11] = xb[12];
       a[12] = xb[13];
       a[13] = xb[14];
       a[14] = xb[15];
       a[15] = xb[8];


       a[16] = xb[19];
       a[17] = xb[20];
       a[18] = xb[21];
       a[19] = xb[22];
       a[20] = xb[23];
       a[21] = xb[16];
       a[22] = xb[17];
       a[23] = xb[18];

       a[24] = xb[28];
       a[25] = xb[29];
       a[26] = xb[30];
       a[27] = xb[31];
       a[28] = xb[24];
       a[29] = xb[25];
       a[30] = xb[26];
       a[31] = xb[27];
    }
    }

    return 1;
}

//--------------------------------------------

int BitRotate(int *a)
{
    int temp[4];
    for(int i = 0; i < 4; i++)
       temp[i] = a[i];

    for(int i = 1; i < 5; i++)
       a[i] = temp[i%4];
}

int mix_c(int *a, bool inv)
{
    int r[4];
    int b[4];
    int h;

    if(inv == false)
    {
          for(int i = 0; i < 4; i++)
          {
             h = a[i] & 0x80;
             b[i] = a[i] << 1;
             if(h == 0x80) 
                b[i] ^= 0x1b;
          }

          r[0] = (b[0] ^ a[3] ^ a[2] ^ b[1] ^ a[1])%256;
          r[1] = (b[1] ^ a[0] ^ a[3] ^ b[2] ^ a[2])%256;
          r[2] = (b[2] ^ a[1] ^ a[0] ^ b[3] ^ a[3])%256;
          r[3] = (b[3] ^ a[2] ^ a[1] ^ b[0] ^ a[0])%256;
    }
    else
    {
        r[0] = (gmul(a[0], 14) ^ gmul(a[3], 9) ^ gmul(a[2], 13) ^ gmul(a[1], 11))%256;
        r[1] = (gmul(a[1], 14) ^ gmul(a[0], 9) ^ gmul(a[3], 13) ^ gmul(a[2], 11))%256;
        r[2] = (gmul(a[2], 14) ^ gmul(a[1], 9) ^ gmul(a[0], 13) ^ gmul(a[3], 11))%256;
        r[3] = (gmul(a[3], 14) ^ gmul(a[2], 9) ^ gmul(a[1], 13) ^ gmul(a[0], 11))%256;
    }

    for(int i = 0; i < 4; i++)
       a[i] = r[i];
    return 1;
}

int gmul(int a, int b)
{
       if(a==0 || b==0)
          return 0;
       else
       {
          if((vlog[a]+vlog[b])>255)
          {
             return alog[(vlog[a]+vlog[b])%256+1];
          }
          else
             return alog[(vlog[a]+vlog[b])];
       }
}

//--------------------------------------------

//DATA ENCRYPTION/DECRYPTION

int data_encrypt(char *buf, int lenght, int *ekey, int bit)
{
   int data[16] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
   for(int j = 0; j < lenght; j++)
   {
       for(int i = 0; i < 15; i++)
          data[i] = data[i+1];
       data[15] = (int)buf[j];
       if(data[15] < 0)
          data[15] += 256;

       for(int i = 0; i < 16; i++)
          cout << data[i] << " ";
       cout << endl;

       encrypt(data, ekey, 128);

       for(int i = 0; i < 16; i++)
          cout << data[i] << " ";
       cout << endl;

       if(data[0] > 127)
          data[0] -= 256;
       buf[j] = (char)data[0];
   }
   for(int j = 1; j < 16; j++)
   {
       if(data[j] > 127)
          data[j] -= 256;
       buf[lenght+2+j] = data[j];
   }
   return 0;
}

int data_decrypt(char *buf, int lenght, int *ekey, int bit)
{
   int data[16];
   for(int i = 0; i < 16; i++)
   {
      data[i] = (int)buf[i+lenght-12];
      if(data[i] < 0)
         data[i] += 256;
   }
   for(int j = lenght-16; j >= 0; j--)
   {
      for(int i = 14; i >= 0; i--)
         data[i+1] = data[i];
      data[0] = (int)buf[j];
      if(data[0] < 0)
         data[0] += 256;

      for(int i = 0; i < 16; i++)
          cout << data[i] << " ";
       cout << endl;

      decrypt(data, ekey, 128);

      for(int i = 0; i < 16; i++)
          cout << data[i] << " ";
      cout << endl;

     if(data[15] > 127)
          data[15] -= 256;
      buf[j] = (char)data[15];
   }
    return 0;
}
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