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rijndael-alg-fst.c

/*
 * rijndael-alg-fst.c   v2.3   April '2000
 *
 * Optimised ANSI C code
 *
 * authors: v1.0: Antoon Bosselaers
 *          v2.0: Vincent Rijmen
 *          v2.3: Paulo Barreto
 *
 * This code is placed in the public domain.
 */

#include "config_xor.h"

#include <stdio.h>
#include <stdlib.h>

#ifdef SH_ENCRYPT

#include "rijndael-alg-fst.h"

#include "rijndael-boxes-fst.h"

int rijndaelKeySched(word8 k[MAXKC][4], word8 W[MAXROUNDS+1][4][4], int ROUNDS) {
      /* Calculate the necessary round keys
       * The number of calculations depends on keyBits and blockBits
       */ 
      int j, r, t, rconpointer = 0;
      word8 tk[MAXKC][4];
      int KC = ROUNDS - 6;

      for (j = KC-1; j >= 0; j--) {
            *((word32*)tk[j]) = *((word32*)k[j]);
      }
      r = 0;
      t = 0;
      /* copy values into round key array */
      for (j = 0; (j < KC) && (r < ROUNDS + 1); ) {
            for (; (j < KC) && (t < 4); j++, t++) {
                  *((word32*)W[r][t]) = *((word32*)tk[j]);
            }
            if (t == 4) {
                  r++;
                  t = 0;
            }
      }
            
      while (r < ROUNDS + 1) { /* while not enough round key material calculated */
            /* calculate new values */
            tk[0][0] ^= S[tk[KC-1][1]];
            tk[0][1] ^= S[tk[KC-1][2]];
            tk[0][2] ^= S[tk[KC-1][3]];
            tk[0][3] ^= S[tk[KC-1][0]];
            tk[0][0] ^= rcon[rconpointer++];

            if (KC != 8) {
                  for (j = 1; j < KC; j++) {
                        *((word32*)tk[j]) ^= *((word32*)tk[j-1]);
                  }
            } else {
                  for (j = 1; j < KC/2; j++) {
                        *((word32*)tk[j]) ^= *((word32*)tk[j-1]);
                  }
                  tk[KC/2][0] ^= S[tk[KC/2 - 1][0]];
                  tk[KC/2][1] ^= S[tk[KC/2 - 1][1]];
                  tk[KC/2][2] ^= S[tk[KC/2 - 1][2]];
                  tk[KC/2][3] ^= S[tk[KC/2 - 1][3]];
                  for (j = KC/2 + 1; j < KC; j++) {
                        *((word32*)tk[j]) ^= *((word32*)tk[j-1]);
                  }
            }
            /* copy values into round key array */
            for (j = 0; (j < KC) && (r < ROUNDS + 1); ) {
                  for (; (j < KC) && (t < 4); j++, t++) {
                        *((word32*)W[r][t]) = *((word32*)tk[j]);
                  }
                  if (t == 4) {
                        r++;
                        t = 0;
                  }
            }
      }           
      return 0;
}

int rijndaelKeyEncToDec(word8 W[MAXROUNDS+1][4][4], int ROUNDS) {
      int r;
      word8 *w;

      for (r = 1; r < ROUNDS; r++) {
            w = W[r][0];
            *((word32*)w) =
                    *((word32*)U1[w[0]])
                  ^ *((word32*)U2[w[1]])
                  ^ *((word32*)U3[w[2]])
                  ^ *((word32*)U4[w[3]]);

            w = W[r][1];
            *((word32*)w) =
                    *((word32*)U1[w[0]])
                  ^ *((word32*)U2[w[1]])
                  ^ *((word32*)U3[w[2]])
                  ^ *((word32*)U4[w[3]]);

            w = W[r][2];
            *((word32*)w) =
                    *((word32*)U1[w[0]])
                  ^ *((word32*)U2[w[1]])
                  ^ *((word32*)U3[w[2]])
                  ^ *((word32*)U4[w[3]]);

            w = W[r][3];
            *((word32*)w) =
                    *((word32*)U1[w[0]])
                  ^ *((word32*)U2[w[1]])
                  ^ *((word32*)U3[w[2]])
                  ^ *((word32*)U4[w[3]]);
      }
      return 0;
}     

/**
 * Encrypt a single block. 
 */
int rijndaelEncrypt(word8 a[16], word8 b[16], word8 rk[MAXROUNDS+1][4][4], int ROUNDS) {
      int r;
      word8 temp[4][4];

    *((word32*)temp[0]) = *((word32*)(a   )) ^ *((word32*)rk[0][0]);
    *((word32*)temp[1]) = *((word32*)(a+ 4)) ^ *((word32*)rk[0][1]);
    *((word32*)temp[2]) = *((word32*)(a+ 8)) ^ *((word32*)rk[0][2]);
    *((word32*)temp[3]) = *((word32*)(a+12)) ^ *((word32*)rk[0][3]);
    *((word32*)(b    )) = *((word32*)T1[temp[0][0]])
                                    ^ *((word32*)T2[temp[1][1]])
                                    ^ *((word32*)T3[temp[2][2]]) 
                                    ^ *((word32*)T4[temp[3][3]]);
    *((word32*)(b + 4)) = *((word32*)T1[temp[1][0]])
                                    ^ *((word32*)T2[temp[2][1]])
                                    ^ *((word32*)T3[temp[3][2]]) 
                                    ^ *((word32*)T4[temp[0][3]]);
    *((word32*)(b + 8)) = *((word32*)T1[temp[2][0]])
                                    ^ *((word32*)T2[temp[3][1]])
                                    ^ *((word32*)T3[temp[0][2]]) 
                                    ^ *((word32*)T4[temp[1][3]]);
    *((word32*)(b +12)) = *((word32*)T1[temp[3][0]])
                                    ^ *((word32*)T2[temp[0][1]])
                                    ^ *((word32*)T3[temp[1][2]]) 
                                    ^ *((word32*)T4[temp[2][3]]);
      for (r = 1; r < ROUNDS-1; r++) {
            *((word32*)temp[0]) = *((word32*)(b   )) ^ *((word32*)rk[r][0]);
            *((word32*)temp[1]) = *((word32*)(b+ 4)) ^ *((word32*)rk[r][1]);
            *((word32*)temp[2]) = *((word32*)(b+ 8)) ^ *((word32*)rk[r][2]);
            *((word32*)temp[3]) = *((word32*)(b+12)) ^ *((word32*)rk[r][3]);

            *((word32*)(b    )) = *((word32*)T1[temp[0][0]])
                                          ^ *((word32*)T2[temp[1][1]])
                                          ^ *((word32*)T3[temp[2][2]]) 
                                          ^ *((word32*)T4[temp[3][3]]);
            *((word32*)(b + 4)) = *((word32*)T1[temp[1][0]])
                                          ^ *((word32*)T2[temp[2][1]])
                                          ^ *((word32*)T3[temp[3][2]]) 
                                          ^ *((word32*)T4[temp[0][3]]);
            *((word32*)(b + 8)) = *((word32*)T1[temp[2][0]])
                                          ^ *((word32*)T2[temp[3][1]])
                                          ^ *((word32*)T3[temp[0][2]]) 
                                          ^ *((word32*)T4[temp[1][3]]);
            *((word32*)(b +12)) = *((word32*)T1[temp[3][0]])
                                          ^ *((word32*)T2[temp[0][1]])
                                          ^ *((word32*)T3[temp[1][2]]) 
                                          ^ *((word32*)T4[temp[2][3]]);
      }
      /* last round is special */   
      *((word32*)temp[0]) = *((word32*)(b   )) ^ *((word32*)rk[ROUNDS-1][0]);
      *((word32*)temp[1]) = *((word32*)(b+ 4)) ^ *((word32*)rk[ROUNDS-1][1]);
      *((word32*)temp[2]) = *((word32*)(b+ 8)) ^ *((word32*)rk[ROUNDS-1][2]);
      *((word32*)temp[3]) = *((word32*)(b+12)) ^ *((word32*)rk[ROUNDS-1][3]);
      b[ 0] = T1[temp[0][0]][1];
      b[ 1] = T1[temp[1][1]][1];
      b[ 2] = T1[temp[2][2]][1];
      b[ 3] = T1[temp[3][3]][1];
      b[ 4] = T1[temp[1][0]][1];
      b[ 5] = T1[temp[2][1]][1];
      b[ 6] = T1[temp[3][2]][1];
      b[ 7] = T1[temp[0][3]][1];
      b[ 8] = T1[temp[2][0]][1];
      b[ 9] = T1[temp[3][1]][1];
      b[10] = T1[temp[0][2]][1];
      b[11] = T1[temp[1][3]][1];
      b[12] = T1[temp[3][0]][1];
      b[13] = T1[temp[0][1]][1];
      b[14] = T1[temp[1][2]][1];
      b[15] = T1[temp[2][3]][1];
      *((word32*)(b   )) ^= *((word32*)rk[ROUNDS][0]);
      *((word32*)(b+ 4)) ^= *((word32*)rk[ROUNDS][1]);
      *((word32*)(b+ 8)) ^= *((word32*)rk[ROUNDS][2]);
      *((word32*)(b+12)) ^= *((word32*)rk[ROUNDS][3]);

      return 0;
}

/**
 * Decrypt a single block.
 */
int rijndaelDecrypt(word8 a[16], word8 b[16], word8 rk[MAXROUNDS+1][4][4], int ROUNDS) {
      int r;
      word8 temp[4][4];
      
    *((word32*)temp[0]) = *((word32*)(a   )) ^ *((word32*)rk[ROUNDS][0]);
    *((word32*)temp[1]) = *((word32*)(a+ 4)) ^ *((word32*)rk[ROUNDS][1]);
    *((word32*)temp[2]) = *((word32*)(a+ 8)) ^ *((word32*)rk[ROUNDS][2]);
    *((word32*)temp[3]) = *((word32*)(a+12)) ^ *((word32*)rk[ROUNDS][3]);

    *((word32*)(b   )) = *((word32*)T5[temp[0][0]])
           ^ *((word32*)T6[temp[3][1]])
           ^ *((word32*)T7[temp[2][2]]) 
           ^ *((word32*)T8[temp[1][3]]);
      *((word32*)(b+ 4)) = *((word32*)T5[temp[1][0]])
           ^ *((word32*)T6[temp[0][1]])
           ^ *((word32*)T7[temp[3][2]]) 
           ^ *((word32*)T8[temp[2][3]]);
      *((word32*)(b+ 8)) = *((word32*)T5[temp[2][0]])
           ^ *((word32*)T6[temp[1][1]])
           ^ *((word32*)T7[temp[0][2]]) 
           ^ *((word32*)T8[temp[3][3]]);
      *((word32*)(b+12)) = *((word32*)T5[temp[3][0]])
           ^ *((word32*)T6[temp[2][1]])
           ^ *((word32*)T7[temp[1][2]]) 
           ^ *((word32*)T8[temp[0][3]]);
      for (r = ROUNDS-1; r > 1; r--) {
            *((word32*)temp[0]) = *((word32*)(b   )) ^ *((word32*)rk[r][0]);
            *((word32*)temp[1]) = *((word32*)(b+ 4)) ^ *((word32*)rk[r][1]);
            *((word32*)temp[2]) = *((word32*)(b+ 8)) ^ *((word32*)rk[r][2]);
            *((word32*)temp[3]) = *((word32*)(b+12)) ^ *((word32*)rk[r][3]);
            *((word32*)(b   )) = *((word32*)T5[temp[0][0]])
           ^ *((word32*)T6[temp[3][1]])
           ^ *((word32*)T7[temp[2][2]]) 
           ^ *((word32*)T8[temp[1][3]]);
            *((word32*)(b+ 4)) = *((word32*)T5[temp[1][0]])
           ^ *((word32*)T6[temp[0][1]])
           ^ *((word32*)T7[temp[3][2]]) 
           ^ *((word32*)T8[temp[2][3]]);
            *((word32*)(b+ 8)) = *((word32*)T5[temp[2][0]])
           ^ *((word32*)T6[temp[1][1]])
           ^ *((word32*)T7[temp[0][2]]) 
           ^ *((word32*)T8[temp[3][3]]);
            *((word32*)(b+12)) = *((word32*)T5[temp[3][0]])
           ^ *((word32*)T6[temp[2][1]])
           ^ *((word32*)T7[temp[1][2]]) 
           ^ *((word32*)T8[temp[0][3]]);
      }
      /* last round is special */   
      *((word32*)temp[0]) = *((word32*)(b   )) ^ *((word32*)rk[1][0]);
      *((word32*)temp[1]) = *((word32*)(b+ 4)) ^ *((word32*)rk[1][1]);
      *((word32*)temp[2]) = *((word32*)(b+ 8)) ^ *((word32*)rk[1][2]);
      *((word32*)temp[3]) = *((word32*)(b+12)) ^ *((word32*)rk[1][3]);
      b[ 0] = S5[temp[0][0]];
      b[ 1] = S5[temp[3][1]];
      b[ 2] = S5[temp[2][2]];
      b[ 3] = S5[temp[1][3]];
      b[ 4] = S5[temp[1][0]];
      b[ 5] = S5[temp[0][1]];
      b[ 6] = S5[temp[3][2]];
      b[ 7] = S5[temp[2][3]];
      b[ 8] = S5[temp[2][0]];
      b[ 9] = S5[temp[1][1]];
      b[10] = S5[temp[0][2]];
      b[11] = S5[temp[3][3]];
      b[12] = S5[temp[3][0]];
      b[13] = S5[temp[2][1]];
      b[14] = S5[temp[1][2]];
      b[15] = S5[temp[0][3]];
      *((word32*)(b   )) ^= *((word32*)rk[0][0]);
      *((word32*)(b+ 4)) ^= *((word32*)rk[0][1]);
      *((word32*)(b+ 8)) ^= *((word32*)rk[0][2]);
      *((word32*)(b+12)) ^= *((word32*)rk[0][3]);

      return 0;
}

#endif

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