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Diffstat (limited to 'openssl/crypto/modes/ctr128.c')
| -rw-r--r-- | openssl/crypto/modes/ctr128.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/openssl/crypto/modes/ctr128.c b/openssl/crypto/modes/ctr128.c new file mode 100644 index 00000000..932037f5 --- /dev/null +++ b/openssl/crypto/modes/ctr128.c @@ -0,0 +1,184 @@ +/* ==================================================================== + * Copyright (c) 2008 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 "modes.h" +#include <string.h> + +#ifndef MODES_DEBUG +# ifndef NDEBUG +# define NDEBUG +# endif +#endif +#include <assert.h> + +typedef unsigned int u32; +typedef unsigned char u8; + +#define STRICT_ALIGNMENT +#if defined(__i386) || defined(__i386__) || \ + defined(__x86_64) || defined(__x86_64__) || \ + defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) || \ + defined(__s390__) || defined(__s390x__) +# undef STRICT_ALIGNMENT +#endif + +/* NOTE: the IV/counter CTR mode is big-endian. The code itself + * is endian-neutral. */ + +/* increment counter (128-bit int) by 1 */ +static void ctr128_inc(unsigned char *counter) { + u32 n=16; + u8 c; + + do { + --n; + c = counter[n]; + ++c; + counter[n] = c; + if (c) return; + } while (n); +} + +#if !defined(OPENSSL_SMALL_FOOTPRINT) +static void ctr128_inc_aligned(unsigned char *counter) { + size_t *data,c,n; + const union { long one; char little; } is_endian = {1}; + + if (is_endian.little) { + ctr128_inc(counter); + return; + } + + data = (size_t *)counter; + n = 16/sizeof(size_t); + do { + --n; + c = data[n]; + ++c; + data[n] = c; + if (c) return; + } while (n); +} +#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, and the + * encrypted counter is kept in ecount_buf. Both *num and + * ecount_buf must be initialised with zeros before the first + * call to CRYPTO_ctr128_encrypt(). + * + * This algorithm assumes that the counter is in the x lower bits + * of the IV (ivec), and that the application has full control over + * overflow and the rest of the IV. This implementation takes NO + * responsability for checking that the counter doesn't overflow + * into the rest of the IV when incremented. + */ +void CRYPTO_ctr128_encrypt(const unsigned char *in, unsigned char *out, + size_t len, const void *key, + unsigned char ivec[16], unsigned char ecount_buf[16], + unsigned int *num, block128_f block) +{ + unsigned int n; + size_t l=0; + + assert(in && out && key && ecount_buf && num); + assert(*num < 16); + + n = *num; + +#if !defined(OPENSSL_SMALL_FOOTPRINT) + if (16%sizeof(size_t) == 0) do { /* always true actually */ + while (n && len) { + *(out++) = *(in++) ^ ecount_buf[n]; + --len; + n = (n+1) % 16; + } + +#if defined(STRICT_ALIGNMENT) + if (((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) + break; +#endif + while (len>=16) { + (*block)(ivec, ecount_buf, key); + ctr128_inc_aligned(ivec); + for (; n<16; n+=sizeof(size_t)) + *(size_t *)(out+n) = + *(size_t *)(in+n) ^ *(size_t *)(ecount_buf+n); + len -= 16; + out += 16; + in += 16; + n = 0; + } + if (len) { + (*block)(ivec, ecount_buf, key); + ctr128_inc_aligned(ivec); + while (len--) { + out[n] = in[n] ^ ecount_buf[n]; + ++n; + } + } + *num = n; + return; + } while(0); + /* the rest would be commonly eliminated by x86* compiler */ +#endif + while (l<len) { + if (n==0) { + (*block)(ivec, ecount_buf, key); + ctr128_inc(ivec); + } + out[l] = in[l] ^ ecount_buf[n]; + ++l; + n = (n+1) % 16; + } + + *num=n; +} |