363 lines
8 KiB
C
363 lines
8 KiB
C
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/*
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* FIPS-197 compliant AES implementation
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*
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* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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/*
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* The AES block cipher was designed by Vincent Rijmen and Joan Daemen.
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*
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* http://csrc.nist.gov/encryption/aes/rijndael/Rijndael.pdf
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* http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf
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*/
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#include <string.h>
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#include "aes.h"
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#include "esp_crypto.h"
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/* Implementation that should never be optimized out by the compiler */
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//static void bzero( void *v, size_t n ) {
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// volatile unsigned char *p = v; while( n-- ) *p++ = 0;
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//}
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void esp_aes_init( AES_CTX *ctx )
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{
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memset( ctx, 0, sizeof( AES_CTX ) );
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AES_LOCK();
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AES_TAKE();
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ets_aes_enable();
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AES_UNLOCK();
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}
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void esp_aes_free( AES_CTX *ctx )
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{
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if ( ctx == NULL ) {
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return;
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}
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bzero( ctx, sizeof( AES_CTX ) );
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AES_LOCK();
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AES_GIVE();
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if (false == AES_IS_USED()) {
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ets_aes_disable();
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}
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AES_UNLOCK();
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}
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/*
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* AES key schedule (encryption)
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*/
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int esp_aes_setkey_enc( AES_CTX *ctx, const unsigned char *key,
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unsigned int keybits )
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{
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enum AES_BITS keybit;
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uint16_t keybyte = keybits / 8;
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switch (keybits) {
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case 128:
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keybit = AES128;
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break;
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case 192:
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keybit = AES192;
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break;
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case 256:
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keybit = AES256;
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break;
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default:
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return ( ERR_AES_INVALID_KEY_LENGTH );
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}
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if (ctx->enc.keyflag == false) {
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ctx->enc.keyflag = true;
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ctx->enc.keybits = keybits;
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memset(ctx->enc.key, 0, sizeof(ctx->enc.key));
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memcpy(ctx->enc.key, key, keybyte);
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} else {
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ets_aes_setkey_enc(key, keybit);
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}
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return 0;
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}
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/*
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* AES key schedule (decryption)
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*/
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int esp_aes_setkey_dec( AES_CTX *ctx, const unsigned char *key,
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unsigned int keybits )
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{
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enum AES_BITS keybit;
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uint16_t keybyte = keybits / 8;
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switch (keybits) {
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case 128:
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keybit = AES128;
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break;
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case 192:
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keybit = AES192;
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break;
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case 256:
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keybit = AES256;
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break;
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default:
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return ( ERR_AES_INVALID_KEY_LENGTH );
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}
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if (ctx->dec.keyflag == false) {
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ctx->dec.keyflag = true;
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ctx->dec.keybits = keybits;
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memset(ctx->dec.key, 0, sizeof(ctx->dec.key));
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memcpy(ctx->dec.key, key, keybyte);
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} else {
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ets_aes_setkey_dec(key, keybit);
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}
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return 0;
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}
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static void esp_aes_process_enable(AES_CTX *ctx, int mode)
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{
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if ( mode == AES_ENCRYPT ) {
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esp_aes_setkey_enc(ctx, ctx->enc.key, ctx->enc.keybits);
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} else {
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esp_aes_setkey_dec(ctx, ctx->dec.key, ctx->dec.keybits);
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}
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return;
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}
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static void esp_aes_process_disable(AES_CTX *ctx, int mode)
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{
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}
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/*
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* AES-ECB block encryption
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*/
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void esp_aes_encrypt( AES_CTX *ctx,
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const unsigned char input[16],
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unsigned char output[16] )
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{
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ets_aes_crypt(input, output);
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return ;
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}
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/*
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* AES-ECB block decryption
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*/
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void esp_aes_decrypt( AES_CTX *ctx,
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const unsigned char input[16],
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unsigned char output[16] )
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{
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ets_aes_crypt(input, output);
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return ;
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}
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/*
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* AES-ECB block encryption/decryption
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*/
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int esp_aes_crypt_ecb( AES_CTX *ctx,
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int mode,
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const unsigned char input[16],
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unsigned char output[16] )
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{
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AES_LOCK();
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esp_aes_process_enable(ctx, mode);
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if ( mode == AES_ENCRYPT ) {
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esp_aes_encrypt( ctx, input, output );
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} else {
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esp_aes_decrypt( ctx, input, output );
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}
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esp_aes_process_disable(ctx, mode);
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AES_UNLOCK();
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return 0;
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}
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/*
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* AES-CBC buffer encryption/decryption
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*/
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int esp_aes_crypt_cbc( AES_CTX *ctx,
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int mode,
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size_t length,
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unsigned char iv[16],
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const unsigned char *input,
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unsigned char *output )
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{
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int i;
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unsigned char temp[16];
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if ( length % 16 ) {
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return ( ERR_AES_INVALID_INPUT_LENGTH );
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}
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if ( mode == AES_DECRYPT ) {
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while ( length > 0 ) {
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memcpy( temp, input, 16 );
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esp_aes_crypt_ecb( ctx, mode, input, output );
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for ( i = 0; i < 16; i++ ) {
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output[i] = (unsigned char)( output[i] ^ iv[i] );
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}
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memcpy( iv, temp, 16 );
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input += 16;
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output += 16;
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length -= 16;
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}
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} else {
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while ( length > 0 ) {
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for ( i = 0; i < 16; i++ ) {
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output[i] = (unsigned char)( input[i] ^ iv[i] );
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}
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esp_aes_crypt_ecb( ctx, mode, output, output );
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memcpy( iv, output, 16 );
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input += 16;
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output += 16;
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length -= 16;
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}
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}
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return 0;
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}
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/*
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* AES-CFB128 buffer encryption/decryption
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*/
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int esp_aes_crypt_cfb128( AES_CTX *ctx,
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int mode,
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size_t length,
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size_t *iv_off,
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unsigned char iv[16],
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const unsigned char *input,
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unsigned char *output )
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{
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int c;
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size_t n = *iv_off;
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if ( mode == AES_DECRYPT ) {
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while ( length-- ) {
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if ( n == 0 ) {
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esp_aes_crypt_ecb( ctx, AES_ENCRYPT, iv, iv );
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}
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c = *input++;
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*output++ = (unsigned char)( c ^ iv[n] );
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iv[n] = (unsigned char) c;
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n = ( n + 1 ) & 0x0F;
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}
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} else {
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while ( length-- ) {
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if ( n == 0 ) {
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esp_aes_crypt_ecb( ctx, AES_ENCRYPT, iv, iv );
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}
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iv[n] = *output++ = (unsigned char)( iv[n] ^ *input++ );
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n = ( n + 1 ) & 0x0F;
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}
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}
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*iv_off = n;
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return 0;
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}
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/*
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* AES-CFB8 buffer encryption/decryption
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*/
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int esp_aes_crypt_cfb8( AES_CTX *ctx,
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int mode,
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size_t length,
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unsigned char iv[16],
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const unsigned char *input,
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unsigned char *output )
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{
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unsigned char c;
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unsigned char ov[17];
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while ( length-- ) {
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memcpy( ov, iv, 16 );
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esp_aes_crypt_ecb( ctx, AES_ENCRYPT, iv, iv );
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if ( mode == AES_DECRYPT ) {
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ov[16] = *input;
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}
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c = *output++ = (unsigned char)( iv[0] ^ *input++ );
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if ( mode == AES_ENCRYPT ) {
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ov[16] = c;
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}
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memcpy( iv, ov + 1, 16 );
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}
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return 0;
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}
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/*
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* AES-CTR buffer encryption/decryption
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*/
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int esp_aes_crypt_ctr( AES_CTX *ctx,
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size_t length,
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size_t *nc_off,
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unsigned char nonce_counter[16],
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unsigned char stream_block[16],
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const unsigned char *input,
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unsigned char *output )
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{
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int c, i;
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size_t n = *nc_off;
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while ( length-- ) {
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if ( n == 0 ) {
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esp_aes_crypt_ecb( ctx, AES_ENCRYPT, nonce_counter, stream_block );
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for ( i = 16; i > 0; i-- )
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if ( ++nonce_counter[i - 1] != 0 ) {
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break;
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}
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}
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c = *input++;
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*output++ = (unsigned char)( c ^ stream_block[n] );
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n = ( n + 1 ) & 0x0F;
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}
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*nc_off = n;
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return 0;
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}
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