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75 lines
2.1 KiB
C
75 lines
2.1 KiB
C
/*
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* Copyright 2008-2016 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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#include <openssl/crypto.h>
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#include "modes_lcl.h"
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#include <string.h>
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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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n = *num;
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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 *)(out + n) =
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*(size_t *)(in + n) ^ *(size_t *)(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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*num = n;
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}
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