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			81 lines
		
	
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			81 lines
		
	
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Copyright 2008-2020 The OpenSSL Project Authors. All Rights Reserved.
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|  *
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|  * Licensed under the OpenSSL license (the "License").  You may not use
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|  * this file except in compliance with the License.  You can obtain a copy
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|  * in the file LICENSE in the source distribution or at
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|  * https://www.openssl.org/source/license.html
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|  */
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| 
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| #include <openssl/crypto.h>
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| #include "modes_local.h"
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| #include <string.h>
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| 
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| #if defined(__GNUC__) && !defined(STRICT_ALIGNMENT)
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| typedef size_t size_t_aX __attribute((__aligned__(1)));
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| #else
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| typedef size_t size_t_aX;
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| #endif
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| 
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| /*
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|  * The input and output encrypted as though 128bit ofb mode is being used.
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|  * The extra state information to record how much of the 128bit block we have
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|  * used is contained in *num;
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|  */
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| void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out,
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|                            size_t len, const void *key,
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|                            unsigned char ivec[16], int *num, block128_f block)
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| {
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|     unsigned int n;
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|     size_t l = 0;
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| 
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|     n = *num;
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| 
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| #if !defined(OPENSSL_SMALL_FOOTPRINT)
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|     if (16 % sizeof(size_t) == 0) { /* always true actually */
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|         do {
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|             while (n && len) {
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|                 *(out++) = *(in++) ^ ivec[n];
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|                 --len;
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|                 n = (n + 1) % 16;
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|             }
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| # if defined(STRICT_ALIGNMENT)
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|             if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) !=
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|                 0)
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|                 break;
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| # endif
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|             while (len >= 16) {
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|                 (*block) (ivec, ivec, key);
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|                 for (; n < 16; n += sizeof(size_t))
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|                     *(size_t_aX *)(out + n) =
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|                         *(size_t_aX *)(in + n)
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|                         ^ *(size_t_aX *)(ivec + n);
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|                 len -= 16;
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|                 out += 16;
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|                 in += 16;
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|                 n = 0;
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|             }
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|             if (len) {
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|                 (*block) (ivec, ivec, key);
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|                 while (len--) {
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|                     out[n] = in[n] ^ ivec[n];
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|                     ++n;
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|                 }
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|             }
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|             *num = n;
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|             return;
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|         } while (0);
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|     }
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|     /* the rest would be commonly eliminated by x86* compiler */
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| #endif
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|     while (l < len) {
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|         if (n == 0) {
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|             (*block) (ivec, ivec, key);
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|         }
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|         out[l] = in[l] ^ ivec[n];
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|         ++l;
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|         n = (n + 1) % 16;
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|     }
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| 
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|     *num = n;
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| }
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