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254 lines
8.8 KiB
254 lines
8.8 KiB
/* ==================================================================== |
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* Copyright (c) 2008 The OpenSSL Project. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* |
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* 3. All advertising materials mentioning features or use of this |
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* software must display the following acknowledgment: |
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* "This product includes software developed by the OpenSSL Project |
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* for use in the OpenSSL Toolkit. (http://www.openssl.org/)" |
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* |
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to |
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* endorse or promote products derived from this software without |
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* prior written permission. For written permission, please contact |
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* openssl-core@openssl.org. |
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* |
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* 5. Products derived from this software may not be called "OpenSSL" |
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* nor may "OpenSSL" appear in their names without prior written |
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* permission of the OpenSSL Project. |
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* |
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* 6. Redistributions of any form whatsoever must retain the following |
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* acknowledgment: |
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* "This product includes software developed by the OpenSSL Project |
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* for use in the OpenSSL Toolkit (http://www.openssl.org/)" |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY |
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR |
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
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* OF THE POSSIBILITY OF SUCH DAMAGE. |
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* ==================================================================== |
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* |
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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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#ifndef MODES_DEBUG |
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# ifndef NDEBUG |
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# define NDEBUG |
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# endif |
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#endif |
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#include <assert.h> |
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/* |
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* The input and output encrypted as though 128bit cfb 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_cfb128_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, |
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int enc, 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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assert(in && out && key && ivec && num); |
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n = *num; |
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if (enc) { |
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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++) = ivec[n] ^= *(in++); |
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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) % |
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sizeof(size_t) != 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 *)(ivec + n) ^= *(size_t *)(in + n); |
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} |
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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] = ivec[n] ^= in[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] = ivec[n] ^= in[l]; |
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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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} else { |
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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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unsigned char c; |
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*(out++) = ivec[n] ^ (c = *(in++)); |
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ivec[n] = c; |
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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) % |
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sizeof(size_t) != 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 t = *(size_t *)(in + n); |
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*(size_t *)(out + n) = *(size_t *)(ivec + n) ^ t; |
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*(size_t *)(ivec + n) = t; |
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} |
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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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unsigned char c; |
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out[n] = ivec[n] ^ (c = in[n]); |
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ivec[n] = c; |
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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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unsigned char c; |
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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] = ivec[n] ^ (c = in[l]); |
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ivec[n] = c; |
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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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} |
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/* |
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* This expects a single block of size nbits for both in and out. Note that |
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* it corrupts any extra bits in the last byte of out |
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*/ |
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static void cfbr_encrypt_block(const unsigned char *in, unsigned char *out, |
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int nbits, const void *key, |
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unsigned char ivec[16], int enc, |
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block128_f block) |
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{ |
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int n, rem, num; |
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unsigned char ovec[16 * 2 + 1]; /* +1 because we dererefence (but don't |
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* use) one byte off the end */ |
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if (nbits <= 0 || nbits > 128) |
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return; |
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/* fill in the first half of the new IV with the current IV */ |
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memcpy(ovec, ivec, 16); |
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/* construct the new IV */ |
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(*block) (ivec, ivec, key); |
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num = (nbits + 7) / 8; |
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if (enc) /* encrypt the input */ |
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for (n = 0; n < num; ++n) |
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out[n] = (ovec[16 + n] = in[n] ^ ivec[n]); |
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else /* decrypt the input */ |
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for (n = 0; n < num; ++n) |
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out[n] = (ovec[16 + n] = in[n]) ^ ivec[n]; |
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/* shift ovec left... */ |
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rem = nbits % 8; |
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num = nbits / 8; |
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if (rem == 0) |
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memcpy(ivec, ovec + num, 16); |
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else |
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for (n = 0; n < 16; ++n) |
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ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem); |
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/* it is not necessary to cleanse ovec, since the IV is not secret */ |
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} |
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/* N.B. This expects the input to be packed, MS bit first */ |
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void CRYPTO_cfb128_1_encrypt(const unsigned char *in, unsigned char *out, |
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size_t bits, const void *key, |
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unsigned char ivec[16], int *num, |
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int enc, block128_f block) |
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{ |
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size_t n; |
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unsigned char c[1], d[1]; |
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assert(in && out && key && ivec && num); |
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assert(*num == 0); |
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for (n = 0; n < bits; ++n) { |
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c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0; |
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cfbr_encrypt_block(c, d, 1, key, ivec, enc, block); |
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out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) | |
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((d[0] & 0x80) >> (unsigned int)(n % 8)); |
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} |
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} |
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void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out, |
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size_t length, const void *key, |
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unsigned char ivec[16], int *num, |
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int enc, block128_f block) |
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{ |
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size_t n; |
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assert(in && out && key && ivec && num); |
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assert(*num == 0); |
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for (n = 0; n < length; ++n) |
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cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block); |
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}
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