Strings Obfuscation System

/**
 ******************************************************************************
 *
 * This code is part of the String Obfuscation Project by Michael Haephrati 
 * The source code is licensed under COMMON DEVELOPMENT AND DISTRIBUTION LICENSE (CDDL)Version 1.1
 * � 2012 Michael Haephrati - haephrati@gmail.com
 * 
 * @file aes256_dec.c
 *
 * @brief @~english Implementatoion of function for encode/decode string.
 *
 *
 *
 *
 * extern "C" wchar_t* __ODC__( const char * );
 ******************************************************************************
 * @n @b encoding:    US-ASCII
 * @n @b tabsize:     8 (not used)
 * @n @b indentation: 2
 */

#include <stdlib.h>
#include <stdio.h>
#include <memory.h>
#include <tchar.h>
#include <string.h>

#ifndef BYTE
#define BYTE  unsigned char
#endif

typedef struct _ref
{
	void * org_str;
	struct _ref *next;
} DECODED_LIST, *PDECODED_LIST;

DECODED_LIST charList = {NULL,NULL};
DECODED_LIST wcharList = {NULL,NULL};

/*
static int w_bufcnt = 0;
static wchar_t * w_buff[16] = {0};
static int w_bufflen[16] = {0};
*/
static wchar_t w_text_err[] = _T("Not enought memory");

/*
static int a_bufcnt = 0;
static char * a_buff[16] = {0};
static int a_bufflen[16] = {0};
*/
static char a_text_err[] = "Not enought memory";
/* -------------------------------------------------------------------------- */

typedef struct 
{
  BYTE key[32]; 
  BYTE enckey[32]; 
  BYTE deckey[32];
} aes_key; 

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

#define rj_sbox_enc(x)  sbox_enc[(x)]
#define rj_sbox_dec(x)  sbox_dec[(x)]

/* -------------------------------------------------------------------------- */
static BYTE rj_xtime(BYTE x) 
{
    return (x & 0x80) ? ((x << 1) ^ 0x1b) : (x << 1);
}

/* -------------------------------------------------------------------------- */
static void aes_subBytes_enc( BYTE *buf )
{
    register BYTE i = 16;

    while (i--) buf[i] = rj_sbox_enc(buf[i]);
}

/* -------------------------------------------------------------------------- */
static void aes_subBytes_dec(BYTE *buf)
{
    register BYTE i = 16;

    while (i--) buf[i] = rj_sbox_dec(buf[i]);
}

/* -------------------------------------------------------------------------- */
static void aes_addRoundKey(BYTE *buf, BYTE *key)
{
    register BYTE i = 16;

    while (i--) buf[i] ^= key[i];
}

/* -------------------------------------------------------------------------- */
static void aes_addRoundKey_cpy( BYTE *buf, BYTE *key, BYTE *cpk )
{
    register BYTE i = 16;

    while (i--)  buf[i] ^= (cpk[i] = key[i]), cpk[16+i] = key[16 + i];
}


/* -------------------------------------------------------------------------- */
static void aes_shiftRows_enc(BYTE *buf)
{
    register BYTE i, j; /* to make it potentially parallelable :) */

    i = buf[1]; buf[1] = buf[5]; buf[5] = buf[9]; buf[9] = buf[13]; buf[13] = i;
    i = buf[10]; buf[10] = buf[2]; buf[2] = i;
    j = buf[3]; buf[3] = buf[15]; buf[15] = buf[11]; buf[11] = buf[7]; buf[7] = j;
    j = buf[14]; buf[14] = buf[6]; buf[6]  = j;

}

/* -------------------------------------------------------------------------- */
static void aes_shiftRows_dec(BYTE *buf)
{
    register BYTE i, j; /* same as above :) */

    i = buf[1]; buf[1] = buf[13]; buf[13] = buf[9]; buf[9] = buf[5]; buf[5] = i;
    i = buf[2]; buf[2] = buf[10]; buf[10] = i;
    j = buf[3]; buf[3] = buf[7]; buf[7] = buf[11]; buf[11] = buf[15]; buf[15] = j;
    j = buf[6]; buf[6] = buf[14]; buf[14] = j;

}

/* -------------------------------------------------------------------------- */
static void aes_mixColumns(BYTE *buf)
{
    register BYTE i, a, b, c, d, e;

    for (i = 0; i < 16; i += 4)
    {
        a = buf[i]; b = buf[i + 1]; c = buf[i + 2]; d = buf[i + 3];
        e = a ^ b ^ c ^ d;
        buf[i] ^= e ^ rj_xtime(a^b);   buf[i+1] ^= e ^ rj_xtime(b^c);
        buf[i+2] ^= e ^ rj_xtime(c^d); buf[i+3] ^= e ^ rj_xtime(d^a);
    }
}

/* -------------------------------------------------------------------------- */
static void aes_mixColumns_inv(BYTE *buf)
{
    register BYTE i, a, b, c, d, e, x, y, z;

    for (i = 0; i < 16; i += 4)
    {
        a = buf[i]; b = buf[i + 1]; c = buf[i + 2]; d = buf[i + 3];
        e = a ^ b ^ c ^ d;
        z = rj_xtime(e);
        x = e ^ rj_xtime(rj_xtime(z^a^c));  y = e ^ rj_xtime(rj_xtime(z^b^d));
        buf[i] ^= x ^ rj_xtime(a^b);   buf[i+1] ^= y ^ rj_xtime(b^c);
        buf[i+2] ^= x ^ rj_xtime(c^d); buf[i+3] ^= y ^ rj_xtime(d^a);
    }
}

/* -------------------------------------------------------------------------- */
static void aes_expandEncKey(BYTE *k, BYTE *rc) 
{
    register BYTE i;

    k[0] ^= rj_sbox_enc(k[29]) ^ (*rc);
    k[1] ^= rj_sbox_enc(k[30]);
    k[2] ^= rj_sbox_enc(k[31]);
    k[3] ^= rj_sbox_enc(k[28]);
    *rc = (((*rc)<<1) ^ ((((*rc)>>7) & 1) * 0x1b));

    for(i = 4; i < 16; i += 4)  k[i] ^= k[i-4],   k[i+1] ^= k[i-3],
        k[i+2] ^= k[i-2], k[i+3] ^= k[i-1];
    k[16] ^= rj_sbox_enc(k[12]);
    k[17] ^= rj_sbox_enc(k[13]);
    k[18] ^= rj_sbox_enc(k[14]);
    k[19] ^= rj_sbox_enc(k[15]);

    for(i = 20; i < 32; i += 4) k[i] ^= k[i-4],   k[i+1] ^= k[i-3],
        k[i+2] ^= k[i-2], k[i+3] ^= k[i-1];

}

/* -------------------------------------------------------------------------- */
static void aes_expandDecKey(BYTE *k, BYTE *rc) 
{
    BYTE i;

    for(i = 28; i > 16; i -= 4) k[i+0] ^= k[i-4], k[i+1] ^= k[i-3], 
        k[i+2] ^= k[i-2], k[i+3] ^= k[i-1];

    k[16] ^= rj_sbox_enc(k[12]);
    k[17] ^= rj_sbox_enc(k[13]);
    k[18] ^= rj_sbox_enc(k[14]);
    k[19] ^= rj_sbox_enc(k[15]);

    for(i = 12; i > 0; i -= 4)  k[i+0] ^= k[i-4], k[i+1] ^= k[i-3],
        k[i+2] ^= k[i-2], k[i+3] ^= k[i-1];

    *rc = (((*rc) >> 1) ^ (((*rc) & 1) ? 0x8d : 0));
    k[0] ^= rj_sbox_enc(k[29]) ^ (*rc);
    k[1] ^= rj_sbox_enc(k[30]);
    k[2] ^= rj_sbox_enc(k[31]);
    k[3] ^= rj_sbox_enc(k[28]);
}


/* -------------------------------------------------------------------------- */
static void aes_prepare( aes_key *key_context, BYTE *k )
{
    BYTE rcon = 1;
    register BYTE i;

    for (i = 0; i < sizeof(key_context->key); i++) key_context->enckey[i] = key_context->deckey[i] = k[i];
    for (i = 8;--i;) aes_expandEncKey(key_context->deckey, &rcon);
}

/* -------------------------------------------------------------------------- */
static void aes_encrypt_block( aes_key *key_context, BYTE *buf )
{
    BYTE i, rcon;

    aes_addRoundKey_cpy( buf, key_context->enckey, key_context->key );
    for(i = 1, rcon = 1; i < 14; ++i)
    {
        aes_subBytes_enc(buf);
        aes_shiftRows_enc(buf);
        aes_mixColumns(buf);
        if( i & 1 ) aes_addRoundKey( buf, &key_context->key[16]);
        else aes_expandEncKey(key_context->key, &rcon), aes_addRoundKey(buf, key_context->key);
    }
    aes_subBytes_enc(buf);
    aes_shiftRows_enc(buf);
    aes_expandEncKey(key_context->key, &rcon); 
    aes_addRoundKey(buf, key_context->key);
}

/* -------------------------------------------------------------------------- */
static void aes_decrypt_block( aes_key *key_context, BYTE *buf )
{
    BYTE i, rcon;

    aes_addRoundKey_cpy(buf, key_context->deckey, key_context->key);
    aes_shiftRows_dec(buf);
    aes_subBytes_dec(buf);

    for (i = 14, rcon = 0x80; --i;)
    {
        if( ( i & 1 ) )           
        {
            aes_expandDecKey(key_context->key, &rcon);
            aes_addRoundKey(buf, &key_context->key[16]);
        }
        else aes_addRoundKey(buf, key_context->key);
        aes_mixColumns_inv(buf);
        aes_shiftRows_dec(buf);
        aes_subBytes_dec(buf);
    }
    aes_addRoundKey( buf, key_context->key); 
}


/* -------------------------------------------------------------------------- */
static int AES_decode( const unsigned char * inbuf, unsigned inlen, void *plainString, unsigned stringSize )
{
  unsigned char key[32];
  aes_key key_context = {0};
  int i;
  BYTE * outbuf = (BYTE*)plainString;

  if( NULL == plainString )
    return -inlen;

  if( stringSize < inlen )
    return 0;

  /** Prepare output buffer */
  memcpy( outbuf, inbuf, inlen );

  /** Prepare key */

  for( i = 0; i < sizeof(key); i++ )
    key[i] = rand();

  aes_prepare( &key_context, key );
  memset( key, 0, sizeof(key) );

  for( i = 0; i < inlen; i += 16 )
  {
    aes_decrypt_block( &key_context, &outbuf[i] );
  }

  memset( &key_context, 0, sizeof(key_context) );

  return inlen;
}

/* -------------------------------------------------------------------------- */
wchar_t* __ODC__( const char * enc_str )
{
  int i, size = strlen( enc_str )/2;
  unsigned char * inBuff = NULL;
  unsigned key = 0;

  PDECODED_LIST ptr = &wcharList;
  wchar_t     * result = w_text_err;


  while( NULL != ptr->next )
  {
	  if( ptr->org_str == enc_str )
		  return (wchar_t*) ((char*)ptr+sizeof(DECODED_LIST));
	  ptr = ptr->next;
  }

  if( NULL == (inBuff = (unsigned char*)malloc( size )) )
    return result; // w_text_error

  if( NULL == (ptr->next = (PDECODED_LIST)malloc( size + sizeof(DECODED_LIST) )) )
  {
    free( inBuff );
    return result; // w_text_error
  }

  ptr = ptr->next;

  ptr->next = NULL;
  ptr->org_str = (void*)enc_str;
  result = (wchar_t*)(((char*)ptr)+sizeof(DECODED_LIST));

  inBuff[0] = ((enc_str[0]-'A')<<4) | (enc_str[1]-enc_str[0]);
  for( i = 1; i < size; i++ )
  {
    int inLen = enc_str[i*2] - enc_str[i*2-1];
    if( 0 > inLen ) inLen += (0x7E-0x20);
    inBuff[i] = (inLen & 0x0F)<<4;
    inLen = enc_str[i*2+1] - enc_str[i*2];
    if( 0 > inLen ) inLen += (0x7E-0x20);
    inBuff[i] |= (inLen & 0x0F);
  }

  srand( *((unsigned*)inBuff) );  // Prepare key to decode
  AES_decode( &inBuff[4], size-4, result, size );
  free( inBuff );
  return result;
}

/* -------------------------------------------------------------------------- */
char* __ODA__( const char * enc_str )
{
  int i, size = strlen( enc_str )/2;
  unsigned char * inBuff = NULL;
  unsigned key = 0;

  PDECODED_LIST ptr = &charList;
  char     * result = a_text_err;


  while( NULL != ptr->next )
  {
	  if( ptr->org_str == enc_str )
		  return ((char*)ptr+sizeof(DECODED_LIST));
	  ptr = ptr->next;
  }

  if( NULL == (inBuff = (unsigned char*)malloc( size )) )
    return result; // a_text_error

  if( NULL == (ptr->next = (PDECODED_LIST)malloc( size + sizeof(DECODED_LIST) )) )
  {
    free( inBuff );
    return result; // a_text_error
  }

  ptr = ptr->next;

  ptr->next = NULL;
  ptr->org_str = (void*)enc_str;
  result = ((char*)ptr)+sizeof(DECODED_LIST);

  
  inBuff[0] = ((enc_str[0]-'A')<<4) | (enc_str[1]-enc_str[0]);
  for( i = 1; i < size; i++ )
  {
    int inLen = enc_str[i*2] - enc_str[i*2-1];
    if( 0 > inLen ) inLen += (0x7E-0x20);
    inBuff[i] = (inLen & 0x0F)<<4;
    inLen = enc_str[i*2+1] - enc_str[i*2];
    if( 0 > inLen ) inLen += (0x7E-0x20);
    inBuff[i] |= (inLen & 0x0F);
  }

  srand( *((unsigned*)inBuff) );  // Prepare key to decode
  AES_decode( &inBuff[4], size-4, result, size );
  free( inBuff );
  return result;
}