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      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 (at) 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 /* NOTE: the IV/counter CTR mode is big-endian.  The rest of the Camellia code
     63  * is endian-neutral. */
     64 /* increment counter (128-bit int) by 1 */
     65 static void Camellia_ctr128_inc(unsigned char *counter)
     66 	{
     67 	unsigned long c;
     68 
     69 	/* Grab bottom dword of counter and increment */
     70 	c = GETU32(counter + 12);
     71 	c++;	c &= 0xFFFFFFFF;
     72 	PUTU32(counter + 12, c);
     73 
     74 	/* if no overflow, we're done */
     75 	if (c)
     76 		return;
     77 
     78 	/* Grab 1st dword of counter and increment */
     79 	c = GETU32(counter +  8);
     80 	c++;	c &= 0xFFFFFFFF;
     81 	PUTU32(counter +  8, c);
     82 
     83 	/* if no overflow, we're done */
     84 	if (c)
     85 		return;
     86 
     87 	/* Grab 2nd dword of counter and increment */
     88 	c = GETU32(counter +  4);
     89 	c++;	c &= 0xFFFFFFFF;
     90 	PUTU32(counter +  4, c);
     91 
     92 	/* if no overflow, we're done */
     93 	if (c)
     94 		return;
     95 
     96 	/* Grab top dword of counter and increment */
     97 	c = GETU32(counter +  0);
     98 	c++;	c &= 0xFFFFFFFF;
     99 	PUTU32(counter +  0, c);
    100 	}
    101 
    102 /* The input encrypted as though 128bit counter mode is being
    103  * used.  The extra state information to record how much of the
    104  * 128bit block we have used is contained in *num, and the
    105  * encrypted counter is kept in ecount_buf.  Both *num and
    106  * ecount_buf must be initialised with zeros before the first
    107  * call to Camellia_ctr128_encrypt().
    108  *
    109  * This algorithm assumes that the counter is in the x lower bits
    110  * of the IV (ivec), and that the application has full control over
    111  * overflow and the rest of the IV.  This implementation takes NO
    112  * responsability for checking that the counter doesn't overflow
    113  * into the rest of the IV when incremented.
    114  */
    115 void Camellia_ctr128_encrypt(const unsigned char *in, unsigned char *out,
    116 	const unsigned long length, const CAMELLIA_KEY *key,
    117 	unsigned char ivec[CAMELLIA_BLOCK_SIZE],
    118 	unsigned char ecount_buf[CAMELLIA_BLOCK_SIZE],
    119 	unsigned int *num)
    120 	{
    121 
    122 	unsigned int n;
    123 	unsigned long l=length;
    124 
    125 	assert(in && out && key && counter && num);
    126 	assert(*num < CAMELLIA_BLOCK_SIZE);
    127 
    128 	n = *num;
    129 
    130 	while (l--)
    131 		{
    132 		if (n == 0)
    133 			{
    134 			Camellia_encrypt(ivec, ecount_buf, key);
    135 			Camellia_ctr128_inc(ivec);
    136 			}
    137 		*(out++) = *(in++) ^ ecount_buf[n];
    138 		n = (n+1) % CAMELLIA_BLOCK_SIZE;
    139 		}
    140 
    141 	*num=n;
    142 	}
    143 
    144