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/* $OpenBSD: xts128.c,v 1.9 2022/11/26 16:08:53 tb Exp $ */
/* ====================================================================
* Copyright (c) 2011 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 <openssl/crypto.h>
#include "modes_local.h"
#include <endian.h>
#include <string.h>
#ifndef MODES_DEBUG
# ifndef NDEBUG
# define NDEBUG
# endif
#endif
int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx, const unsigned char iv[16],
const unsigned char *inp, unsigned char *out,
size_t len, int enc)
{
union { u64 u[2]; u32 d[4]; u8 c[16]; } tweak, scratch;
unsigned int i;
if (len<16) return -1;
memcpy(tweak.c, iv, 16);
(*ctx->block2)(tweak.c,tweak.c,ctx->key2);
if (!enc && (len%16)) len-=16;
while (len>=16) {
#ifdef __STRICT_ALIGNMENT
memcpy(scratch.c,inp,16);
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
#else
scratch.u[0] = ((u64*)inp)[0]^tweak.u[0];
scratch.u[1] = ((u64*)inp)[1]^tweak.u[1];
#endif
(*ctx->block1)(scratch.c,scratch.c,ctx->key1);
#ifdef __STRICT_ALIGNMENT
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
memcpy(out,scratch.c,16);
#else
((u64*)out)[0] = scratch.u[0]^=tweak.u[0];
((u64*)out)[1] = scratch.u[1]^=tweak.u[1];
#endif
inp += 16;
out += 16;
len -= 16;
if (len==0) return 0;
#if BYTE_ORDER == LITTLE_ENDIAN
unsigned int carry,res;
res = 0x87&(((int)tweak.d[3])>>31);
carry = (unsigned int)(tweak.u[0]>>63);
tweak.u[0] = (tweak.u[0]<<1)^res;
tweak.u[1] = (tweak.u[1]<<1)|carry;
#else /* BIG_ENDIAN */
size_t c;
for (c=0,i=0;i<16;++i) {
/*+ substitutes for |, because c is 1 bit */
c += ((size_t)tweak.c[i])<<1;
tweak.c[i] = (u8)c;
c = c>>8;
}
tweak.c[0] ^= (u8)(0x87&(0-c));
#endif
}
if (enc) {
for (i=0;i<len;++i) {
u8 c = inp[i];
out[i] = scratch.c[i];
scratch.c[i] = c;
}
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
(*ctx->block1)(scratch.c,scratch.c,ctx->key1);
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
memcpy(out-16,scratch.c,16);
}
else {
union { u64 u[2]; u8 c[16]; } tweak1;
#if BYTE_ORDER == LITTLE_ENDIAN
unsigned int carry,res;
res = 0x87&(((int)tweak.d[3])>>31);
carry = (unsigned int)(tweak.u[0]>>63);
tweak1.u[0] = (tweak.u[0]<<1)^res;
tweak1.u[1] = (tweak.u[1]<<1)|carry;
#else
size_t c;
for (c=0,i=0;i<16;++i) {
/*+ substitutes for |, because c is 1 bit */
c += ((size_t)tweak.c[i])<<1;
tweak1.c[i] = (u8)c;
c = c>>8;
}
tweak1.c[0] ^= (u8)(0x87&(0-c));
#endif
#ifdef __STRICT_ALIGNMENT
memcpy(scratch.c,inp,16);
scratch.u[0] ^= tweak1.u[0];
scratch.u[1] ^= tweak1.u[1];
#else
scratch.u[0] = ((u64*)inp)[0]^tweak1.u[0];
scratch.u[1] = ((u64*)inp)[1]^tweak1.u[1];
#endif
(*ctx->block1)(scratch.c,scratch.c,ctx->key1);
scratch.u[0] ^= tweak1.u[0];
scratch.u[1] ^= tweak1.u[1];
for (i=0;i<len;++i) {
u8 c = inp[16+i];
out[16+i] = scratch.c[i];
scratch.c[i] = c;
}
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
(*ctx->block1)(scratch.c,scratch.c,ctx->key1);
#ifdef __STRICT_ALIGNMENT
scratch.u[0] ^= tweak.u[0];
scratch.u[1] ^= tweak.u[1];
memcpy (out,scratch.c,16);
#else
((u64*)out)[0] = scratch.u[0]^tweak.u[0];
((u64*)out)[1] = scratch.u[1]^tweak.u[1];
#endif
}
return 0;
}
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