crypto/rc4/rc4_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 /*
  11  * RC4 low level APIs are deprecated for public use, but still ok for internal
  12  * use.
  13  */
  14 #include "internal/deprecated.h"
  15
  16 #include <openssl/rc4.h>
  17 #include "rc4_local.h"
  18 #include <openssl/opensslv.h>
  19
  20 const char *RC4_options(void)
  21 {
  22     if (sizeof(RC4_INT) == 1)
  23         return "rc4(char)";
  24     else
  25         return "rc4(int)";
  26 }
  27
  28 /*-
  29  * RC4 as implemented from a posting from
  30  * Newsgroups: sci.crypt
  31  * Subject: RC4 Algorithm revealed.
  32  * Message-ID: <sternCvKL4B.Hyy@netcom.com>
  33  * Date: Wed, 14 Sep 1994 06:35:31 GMT
  34  */
  35
  36 void RC4_set_key(RC4_KEY *key, int len, const unsigned char *data)
  37 {
  38     register RC4_INT tmp;
  39     register int id1, id2;
  40     register RC4_INT *d;
  41     unsigned int i;
  42
  43     d = &(key->data[0]);
  44     key->x = 0;
  45     key->y = 0;
  46     id1 = id2 = 0;
  47
  48 #define SK_LOOP(d,n) { \
  49                 tmp=d[(n)]; \
  50                 id2 = (data[id1] + tmp + id2) & 0xff; \
  51                 if (++id1 == len) id1=0; \
  52                 d[(n)]=d[id2]; \
  53                 d[id2]=tmp; }
  54
  55     for (i = 0; i < 256; i++)
  56         d[i] = i;
  57     for (i = 0; i < 256; i += 4) {
  58         SK_LOOP(d, i + 0);
  59         SK_LOOP(d, i + 1);
  60         SK_LOOP(d, i + 2);
  61         SK_LOOP(d, i + 3);
  62     }
  63 }