crypto/rc5/rc5_skey.c

   1 /*
   2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <openssl/rc5.h>
  11 #include "rc5_locl.h"
  12
  13 void RC5_32_set_key(RC5_32_KEY *key, int len, const unsigned char *data,
  14                     int rounds)
  15 {
  16     RC5_32_INT L[64], l, ll, A, B, *S, k;
  17     int i, j, m, c, t, ii, jj;
  18
  19     if ((rounds != RC5_16_ROUNDS) &&
  20         (rounds != RC5_12_ROUNDS) && (rounds != RC5_8_ROUNDS))
  21         rounds = RC5_16_ROUNDS;
  22
  23     key->rounds = rounds;
  24     S = &(key->data[0]);
  25     j = 0;
  26     for (i = 0; i <= (len - 8); i += 8) {
  27         c2l(data, l);
  28         L[j++] = l;
  29         c2l(data, l);
  30         L[j++] = l;
  31     }
  32     ii = len - i;
  33     if (ii) {
  34         k = len & 0x07;
  35         c2ln(data, l, ll, k);
  36         L[j + 0] = l;
  37         L[j + 1] = ll;
  38     }
  39
  40     c = (len + 3) / 4;
  41     t = (rounds + 1) * 2;
  42     S[0] = RC5_32_P;
  43     for (i = 1; i < t; i++)
  44         S[i] = (S[i - 1] + RC5_32_Q) & RC5_32_MASK;
  45
  46     j = (t > c) ? t : c;
  47     j *= 3;
  48     ii = jj = 0;
  49     A = B = 0;
  50     for (i = 0; i < j; i++) {
  51         k = (S[ii] + A + B) & RC5_32_MASK;
  52         A = S[ii] = ROTATE_l32(k, 3);
  53         m = (int)(A + B);
  54         k = (L[jj] + A + B) & RC5_32_MASK;
  55         B = L[jj] = ROTATE_l32(k, m);
  56         if (++ii >= t)
  57             ii = 0;
  58         if (++jj >= c)
  59             jj = 0;
  60     }
  61 }