117 lines
3.8 KiB
C
117 lines
3.8 KiB
C
/* crypto/aes/aes_ctr.c -*- mode:C; c-file-style: "eay" -*- */
|
|
/* ====================================================================
|
|
* Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
*
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
*
|
|
* 3. All advertising materials mentioning features or use of this
|
|
* software must display the following acknowledgment:
|
|
* "This product includes software developed by the OpenSSL Project
|
|
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
|
|
*
|
|
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
|
|
* endorse or promote products derived from this software without
|
|
* prior written permission. For written permission, please contact
|
|
* openssl-core@openssl.org.
|
|
*
|
|
* 5. Products derived from this software may not be called "OpenSSL"
|
|
* nor may "OpenSSL" appear in their names without prior written
|
|
* permission of the OpenSSL Project.
|
|
*
|
|
* 6. Redistributions of any form whatsoever must retain the following
|
|
* acknowledgment:
|
|
* "This product includes software developed by the OpenSSL Project
|
|
* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
|
|
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
|
|
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
|
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
|
|
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
|
|
* OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
* ====================================================================
|
|
*
|
|
*/
|
|
|
|
#include <assert.h>
|
|
#include <openssl/aes.h>
|
|
#include "aes_locl.h"
|
|
|
|
/* NOTE: CTR mode is big-endian. The rest of the AES code
|
|
* is endian-neutral. */
|
|
|
|
/* increment counter (128-bit int) by 2^64 */
|
|
static void AES_ctr128_inc(unsigned char *counter) {
|
|
unsigned long c;
|
|
|
|
/* Grab 3rd dword of counter and increment */
|
|
#ifdef L_ENDIAN
|
|
c = GETU32(counter + 8);
|
|
c++;
|
|
PUTU32(counter + 8, c);
|
|
#else
|
|
c = GETU32(counter + 4);
|
|
c++;
|
|
PUTU32(counter + 4, c);
|
|
#endif
|
|
|
|
/* if no overflow, we're done */
|
|
if (c)
|
|
return;
|
|
|
|
/* Grab top dword of counter and increment */
|
|
#ifdef L_ENDIAN
|
|
c = GETU32(counter + 12);
|
|
c++;
|
|
PUTU32(counter + 12, c);
|
|
#else
|
|
c = GETU32(counter + 0);
|
|
c++;
|
|
PUTU32(counter + 0, c);
|
|
#endif
|
|
|
|
}
|
|
|
|
/* The input encrypted as though 128bit counter mode is being
|
|
* used. The extra state information to record how much of the
|
|
* 128bit block we have used is contained in *num;
|
|
*/
|
|
void AES_ctr128_encrypt(const unsigned char *in, unsigned char *out,
|
|
const unsigned long length, const AES_KEY *key,
|
|
unsigned char *counter, unsigned int *num) {
|
|
|
|
unsigned int n;
|
|
unsigned long l=length;
|
|
unsigned char tmp[AES_BLOCK_SIZE];
|
|
|
|
assert(in && out && key && counter && num);
|
|
|
|
n = *num;
|
|
|
|
while (l--) {
|
|
if (n == 0) {
|
|
AES_encrypt(counter, tmp, key);
|
|
AES_ctr128_inc(counter);
|
|
}
|
|
*(out++) = *(in++) ^ tmp[n];
|
|
n = (n+1) % AES_BLOCK_SIZE;
|
|
}
|
|
|
|
*num=n;
|
|
}
|