crypto/camellia/cmll_ctr.c

   1 /* crypto/camellia/camellia_ctr.c -*- mode:C; c-file-style: "eay" -*- */
   2 /* ====================================================================
   3  * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in
  14  *    the documentation and/or other materials provided with the
  15  *    distribution.
  16  *
  17  * 3. All advertising materials mentioning features or use of this
  18  *    software must display the following acknowledgment:
  19  *    "This product includes software developed by the OpenSSL Project
  20  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  21  *
  22  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  23  *    endorse or promote products derived from this software without
  24  *    prior written permission. For written permission, please contact
  25  *    openssl-core@openssl.org.
  26  *
  27  * 5. Products derived from this software may not be called "OpenSSL"
  28  *    nor may "OpenSSL" appear in their names without prior written
  29  *    permission of the OpenSSL Project.
  30  *
  31  * 6. Redistributions of any form whatsoever must retain the following
  32  *    acknowledgment:
  33  *    "This product includes software developed by the OpenSSL Project
  34  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  35  *
  36  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  37  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  39  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  42  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  43  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  45  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  46  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  47  * OF THE POSSIBILITY OF SUCH DAMAGE.
  48  * ====================================================================
  49  *
  50  */
  51
  52 #ifndef CAMELLIA_DEBUG
  53 # ifndef NDEBUG
  54 #  define NDEBUG
  55 # endif
  56 #endif
  57 #include <assert.h>
  58
  59 #include <openssl/camellia.h>
  60 #include "cmll_locl.h"
  61
  62 /*
  63  * NOTE: the IV/counter CTR mode is big-endian.  The rest of the Camellia
  64  * code is endian-neutral.
  65  */
  66 /* increment counter (128-bit int) by 1 */
  67 static void Camellia_ctr128_inc(unsigned char *counter)
  68 {
  69     unsigned long c;
  70
  71     /* Grab bottom dword of counter and increment */
  72     c = GETU32(counter + 12);
  73     c++;
  74     c &= 0xFFFFFFFF;
  75     PUTU32(counter + 12, c);
  76
  77     /* if no overflow, we're done */
  78     if (c)
  79         return;
  80
  81     /* Grab 1st dword of counter and increment */
  82     c = GETU32(counter + 8);
  83     c++;
  84     c &= 0xFFFFFFFF;
  85     PUTU32(counter + 8, c);
  86
  87     /* if no overflow, we're done */
  88     if (c)
  89         return;
  90
  91     /* Grab 2nd dword of counter and increment */
  92     c = GETU32(counter + 4);
  93     c++;
  94     c &= 0xFFFFFFFF;
  95     PUTU32(counter + 4, c);
  96
  97     /* if no overflow, we're done */
  98     if (c)
  99         return;
 100
 101     /* Grab top dword of counter and increment */
 102     c = GETU32(counter + 0);
 103     c++;
 104     c &= 0xFFFFFFFF;
 105     PUTU32(counter + 0, c);
 106 }
 107
 108 /*
 109  * The input encrypted as though 128bit counter mode is being used.  The
 110  * extra state information to record how much of the 128bit block we have
 111  * used is contained in *num, and the encrypted counter is kept in
 112  * ecount_buf.  Both *num and ecount_buf must be initialised with zeros
 113  * before the first call to Camellia_ctr128_encrypt(). This algorithm
 114  * assumes that the counter is in the x lower bits of the IV (ivec), and that
 115  * the application has full control over overflow and the rest of the IV.
 116  * This implementation takes NO responsability for checking that the counter
 117  * doesn't overflow into the rest of the IV when incremented.
 118  */
 119 void Camellia_ctr128_encrypt(const unsigned char *in, unsigned char *out,
 120                              const unsigned long length,
 121                              const CAMELLIA_KEY *key,
 122                              unsigned char ivec[CAMELLIA_BLOCK_SIZE],
 123                              unsigned char ecount_buf[CAMELLIA_BLOCK_SIZE],
 124                              unsigned int *num)
 125 {
 126
 127     unsigned int n;
 128     unsigned long l = length;
 129
 130     assert(in && out && key && counter && num);
 131     assert(*num < CAMELLIA_BLOCK_SIZE);
 132
 133     n = *num;
 134
 135     while (l--) {
 136         if (n == 0) {
 137             Camellia_encrypt(ivec, ecount_buf, key);
 138             Camellia_ctr128_inc(ivec);
 139         }
 140         *(out++) = *(in++) ^ ecount_buf[n];
 141         n = (n + 1) % CAMELLIA_BLOCK_SIZE;
 142     }
 143
 144     *num = n;
 145 }