445 lines
12 KiB
C
445 lines
12 KiB
C
![]() |
/*
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* aes_cbc.c
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*
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* AES Cipher Block Chaining Mode
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*
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* David A. McGrew
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* Cisco Systems, Inc.
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*/
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/*
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*
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* Copyright (c) 2001-2005, Cisco Systems, Inc.
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* 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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* 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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* Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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*
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* Neither the name of the Cisco Systems, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; 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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#include "aes_cbc.h"
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#include "alloc.h"
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debug_module_t mod_aes_cbc = {
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0, /* debugging is off by default */
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"aes cbc" /* printable module name */
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};
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err_status_t
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aes_cbc_alloc(cipher_t **c, int key_len) {
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extern cipher_type_t aes_cbc;
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uint8_t *pointer;
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int tmp;
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debug_print(mod_aes_cbc,
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"allocating cipher with key length %d", key_len);
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if (key_len != 16)
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return err_status_bad_param;
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/* allocate memory a cipher of type aes_icm */
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tmp = (sizeof(aes_cbc_ctx_t) + sizeof(cipher_t));
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pointer = crypto_alloc(tmp);
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if (pointer == NULL)
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return err_status_alloc_fail;
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/* set pointers */
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*c = (cipher_t *)pointer;
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(*c)->type = &aes_cbc;
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(*c)->state = pointer + sizeof(cipher_t);
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/* increment ref_count */
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aes_cbc.ref_count++;
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/* set key size */
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(*c)->key_len = key_len;
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return err_status_ok;
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}
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err_status_t
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aes_cbc_dealloc(cipher_t *c) {
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extern cipher_type_t aes_cbc;
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/* zeroize entire state*/
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octet_string_set_to_zero((uint8_t *)c,
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sizeof(aes_cbc_ctx_t) + sizeof(cipher_t));
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/* free memory */
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crypto_free(c);
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/* decrement ref_count */
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aes_cbc.ref_count--;
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return err_status_ok;
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}
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err_status_t
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aes_cbc_context_init(aes_cbc_ctx_t *c, const uint8_t *key,
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cipher_direction_t dir) {
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v128_t tmp_key;
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/* set tmp_key (for alignment) */
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v128_copy_octet_string(&tmp_key, key);
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debug_print(mod_aes_cbc,
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"key: %s", v128_hex_string(&tmp_key));
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/* expand key for the appropriate direction */
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switch (dir) {
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case (direction_encrypt):
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aes_expand_encryption_key(&tmp_key, c->expanded_key);
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break;
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case (direction_decrypt):
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aes_expand_decryption_key(&tmp_key, c->expanded_key);
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break;
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default:
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return err_status_bad_param;
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}
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return err_status_ok;
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}
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err_status_t
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aes_cbc_set_iv(aes_cbc_ctx_t *c, void *iv) {
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int i;
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/* v128_t *input = iv; */
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uint8_t *input = iv;
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/* set state and 'previous' block to iv */
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for (i=0; i < 16; i++)
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c->previous.v8[i] = c->state.v8[i] = input[i];
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debug_print(mod_aes_cbc, "setting iv: %s", v128_hex_string(&c->state));
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return err_status_ok;
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}
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err_status_t
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aes_cbc_encrypt(aes_cbc_ctx_t *c,
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unsigned char *data,
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unsigned int *bytes_in_data) {
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int i;
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unsigned char *input = data; /* pointer to data being read */
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unsigned char *output = data; /* pointer to data being written */
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int bytes_to_encr = *bytes_in_data;
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/*
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* verify that we're 16-octet aligned
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*/
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if (*bytes_in_data & 0xf)
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return err_status_bad_param;
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/*
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* note that we assume that the initialization vector has already
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* been set, e.g. by calling aes_cbc_set_iv()
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*/
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debug_print(mod_aes_cbc, "iv: %s",
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v128_hex_string(&c->state));
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/*
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* loop over plaintext blocks, exoring state into plaintext then
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* encrypting and writing to output
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*/
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while (bytes_to_encr > 0) {
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/* exor plaintext into state */
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for (i=0; i < 16; i++)
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c->state.v8[i] ^= *input++;
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debug_print(mod_aes_cbc, "inblock: %s",
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v128_hex_string(&c->state));
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aes_encrypt(&c->state, c->expanded_key);
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debug_print(mod_aes_cbc, "outblock: %s",
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v128_hex_string(&c->state));
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/* copy ciphertext to output */
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for (i=0; i < 16; i++)
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*output++ = c->state.v8[i];
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bytes_to_encr -= 16;
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}
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return err_status_ok;
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}
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err_status_t
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aes_cbc_decrypt(aes_cbc_ctx_t *c,
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unsigned char *data,
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unsigned int *bytes_in_data) {
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int i;
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v128_t state, previous;
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unsigned char *input = data; /* pointer to data being read */
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unsigned char *output = data; /* pointer to data being written */
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int bytes_to_encr = *bytes_in_data;
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uint8_t tmp;
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/*
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* verify that we're 16-octet aligned
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*/
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if (*bytes_in_data & 0x0f)
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return err_status_bad_param;
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/* set 'previous' block to iv*/
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for (i=0; i < 16; i++) {
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previous.v8[i] = c->previous.v8[i];
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}
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debug_print(mod_aes_cbc, "iv: %s",
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v128_hex_string(&previous));
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/*
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* loop over ciphertext blocks, decrypting then exoring with state
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* then writing plaintext to output
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*/
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while (bytes_to_encr > 0) {
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/* set state to ciphertext input block */
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for (i=0; i < 16; i++) {
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state.v8[i] = *input++;
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}
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debug_print(mod_aes_cbc, "inblock: %s",
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v128_hex_string(&state));
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/* decrypt state */
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aes_decrypt(&state, c->expanded_key);
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debug_print(mod_aes_cbc, "outblock: %s",
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v128_hex_string(&state));
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/*
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* exor previous ciphertext block out of plaintext, and write new
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* plaintext block to output, while copying old ciphertext block
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* to the 'previous' block
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*/
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for (i=0; i < 16; i++) {
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tmp = *output;
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*output++ = state.v8[i] ^ previous.v8[i];
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previous.v8[i] = tmp;
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}
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bytes_to_encr -= 16;
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}
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return err_status_ok;
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}
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err_status_t
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aes_cbc_nist_encrypt(aes_cbc_ctx_t *c,
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unsigned char *data,
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unsigned int *bytes_in_data) {
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int i;
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unsigned char *pad_start;
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int num_pad_bytes;
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err_status_t status;
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/*
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* determine the number of padding bytes that we need to add -
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* this value is always between 1 and 16, inclusive.
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*/
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num_pad_bytes = 16 - (*bytes_in_data & 0xf);
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pad_start = data;
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pad_start += *bytes_in_data;
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*pad_start++ = 0xa0;
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for (i=0; i < num_pad_bytes; i++)
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*pad_start++ = 0x00;
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/*
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* increment the data size
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*/
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*bytes_in_data += num_pad_bytes;
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/*
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* now cbc encrypt the padded data
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*/
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status = aes_cbc_encrypt(c, data, bytes_in_data);
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if (status)
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return status;
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return err_status_ok;
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}
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err_status_t
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aes_cbc_nist_decrypt(aes_cbc_ctx_t *c,
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unsigned char *data,
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unsigned int *bytes_in_data) {
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unsigned char *pad_end;
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int num_pad_bytes;
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err_status_t status;
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/*
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* cbc decrypt the padded data
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*/
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status = aes_cbc_decrypt(c, data, bytes_in_data);
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if (status)
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return status;
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/*
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* determine the number of padding bytes in the decrypted plaintext
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* - this value is always between 1 and 16, inclusive.
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*/
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num_pad_bytes = 1;
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pad_end = data + (*bytes_in_data - 1);
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while (*pad_end != 0xa0) { /* note: should check padding correctness */
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pad_end--;
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num_pad_bytes++;
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}
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/* decrement data size */
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*bytes_in_data -= num_pad_bytes;
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return err_status_ok;
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}
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char
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aes_cbc_description[] = "aes cipher block chaining (cbc) mode";
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/*
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* Test case 0 is derived from FIPS 197 Appendix A; it uses an
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* all-zero IV, so that the first block encryption matches the test
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* case in that appendix. This property provides a check of the base
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* AES encryption and decryption algorithms; if CBC fails on some
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* particular platform, then you should print out AES intermediate
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* data and compare with the detailed info provided in that appendix.
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*
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*/
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uint8_t aes_cbc_test_case_0_key[16] = {
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0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
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};
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uint8_t aes_cbc_test_case_0_plaintext[64] = {
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0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
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0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff
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};
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uint8_t aes_cbc_test_case_0_ciphertext[80] = {
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0x69, 0xc4, 0xe0, 0xd8, 0x6a, 0x7b, 0x04, 0x30,
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0xd8, 0xcd, 0xb7, 0x80, 0x70, 0xb4, 0xc5, 0x5a,
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0x03, 0x35, 0xed, 0x27, 0x67, 0xf2, 0x6d, 0xf1,
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0x64, 0x83, 0x2e, 0x23, 0x44, 0x38, 0x70, 0x8b
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};
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uint8_t aes_cbc_test_case_0_iv[16] = {
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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cipher_test_case_t aes_cbc_test_case_0 = {
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16, /* octets in key */
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aes_cbc_test_case_0_key, /* key */
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aes_cbc_test_case_0_iv, /* initialization vector */
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16, /* octets in plaintext */
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aes_cbc_test_case_0_plaintext, /* plaintext */
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32, /* octets in ciphertext */
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aes_cbc_test_case_0_ciphertext, /* ciphertext */
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NULL /* pointer to next testcase */
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};
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/*
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* this test case is taken directly from Appendix F.2 of NIST Special
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* Publication SP 800-38A
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*/
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uint8_t aes_cbc_test_case_1_key[16] = {
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0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
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0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c,
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};
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uint8_t aes_cbc_test_case_1_plaintext[64] = {
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0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
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0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
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0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
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0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
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0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
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0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
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0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,
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0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10
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};
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uint8_t aes_cbc_test_case_1_ciphertext[80] = {
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0x76, 0x49, 0xab, 0xac, 0x81, 0x19, 0xb2, 0x46,
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0xce, 0xe9, 0x8e, 0x9b, 0x12, 0xe9, 0x19, 0x7d,
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0x50, 0x86, 0xcb, 0x9b, 0x50, 0x72, 0x19, 0xee,
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0x95, 0xdb, 0x11, 0x3a, 0x91, 0x76, 0x78, 0xb2,
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0x73, 0xbe, 0xd6, 0xb8, 0xe3, 0xc1, 0x74, 0x3b,
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0x71, 0x16, 0xe6, 0x9e, 0x22, 0x22, 0x95, 0x16,
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0x3f, 0xf1, 0xca, 0xa1, 0x68, 0x1f, 0xac, 0x09,
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0x12, 0x0e, 0xca, 0x30, 0x75, 0x86, 0xe1, 0xa7,
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0x39, 0x34, 0x07, 0x03, 0x36, 0xd0, 0x77, 0x99,
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0xe0, 0xc4, 0x2f, 0xdd, 0xa8, 0xdf, 0x4c, 0xa3
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};
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uint8_t aes_cbc_test_case_1_iv[16] = {
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||
|
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
|
||
|
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
|
||
|
};
|
||
|
|
||
|
cipher_test_case_t aes_cbc_test_case_1 = {
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||
|
16, /* octets in key */
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||
|
aes_cbc_test_case_1_key, /* key */
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||
|
aes_cbc_test_case_1_iv, /* initialization vector */
|
||
|
64, /* octets in plaintext */
|
||
|
aes_cbc_test_case_1_plaintext, /* plaintext */
|
||
|
80, /* octets in ciphertext */
|
||
|
aes_cbc_test_case_1_ciphertext, /* ciphertext */
|
||
|
&aes_cbc_test_case_0 /* pointer to next testcase */
|
||
|
};
|
||
|
|
||
|
cipher_type_t aes_cbc = {
|
||
|
(cipher_alloc_func_t) aes_cbc_alloc,
|
||
|
(cipher_dealloc_func_t) aes_cbc_dealloc,
|
||
|
(cipher_init_func_t) aes_cbc_context_init,
|
||
|
(cipher_encrypt_func_t) aes_cbc_nist_encrypt,
|
||
|
(cipher_decrypt_func_t) aes_cbc_nist_decrypt,
|
||
|
(cipher_set_iv_func_t) aes_cbc_set_iv,
|
||
|
(char *) aes_cbc_description,
|
||
|
(int) 0, /* instance count */
|
||
|
(cipher_test_case_t *) &aes_cbc_test_case_0,
|
||
|
(debug_module_t *) &mod_aes_cbc
|
||
|
};
|
||
|
|
||
|
|