1 /* 2 * Copyright 2008-2016 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 #include <openssl/crypto.h> 11 #include "modes_local.h" 12 #include <string.h> 13 14 /* 15 * The input and output encrypted as though 128bit ofb mode is being used. 16 * The extra state information to record how much of the 128bit block we have 17 * used is contained in *num; 18 */ 19 void CRYPTO_ofb128_encrypt(const unsigned char *in, unsigned char *out, 20 size_t len, const void *key, 21 unsigned char ivec[16], int *num, block128_f block) 22 { 23 unsigned int n; 24 size_t l = 0; 25 26 n = *num; 27 28 #if !defined(OPENSSL_SMALL_FOOTPRINT) 29 if (16 % sizeof(size_t) == 0) { /* always true actually */ 30 do { 31 while (n && len) { 32 *(out++) = *(in++) ^ ivec[n]; 33 --len; 34 n = (n + 1) % 16; 35 } 36 # if defined(STRICT_ALIGNMENT) 37 if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 38 0) 39 break; 40 # endif 41 while (len >= 16) { 42 (*block) (ivec, ivec, key); 43 for (; n < 16; n += sizeof(size_t)) 44 *(size_t *)(out + n) = 45 *(size_t *)(in + n) ^ *(size_t *)(ivec + n); 46 len -= 16; 47 out += 16; 48 in += 16; 49 n = 0; 50 } 51 if (len) { 52 (*block) (ivec, ivec, key); 53 while (len--) { 54 out[n] = in[n] ^ ivec[n]; 55 ++n; 56 } 57 } 58 *num = n; 59 return; 60 } while (0); 61 } 62 /* the rest would be commonly eliminated by x86* compiler */ 63 #endif 64 while (l < len) { 65 if (n == 0) { 66 (*block) (ivec, ivec, key); 67 } 68 out[l] = in[l] ^ ivec[n]; 69 ++l; 70 n = (n + 1) % 16; 71 } 72 73 *num = n; 74 } 75