304 lines
7.3 KiB
C
304 lines
7.3 KiB
C
/* aes-cfb.c
|
|
*
|
|
* Copyright (C) 2006-2025 wolfSSL Inc.
|
|
*
|
|
* This file is part of wolfSSL.
|
|
*
|
|
* wolfSSL is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* wolfSSL is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
|
|
*/
|
|
|
|
/* AES-CFB Example
|
|
* This example demonstrates:
|
|
* - One-shot encryption using wc_AesCfbEncrypt()
|
|
* - Streaming decryption using wc_AesCfbDecrypt() in chunks
|
|
* Note: CFB mode inherently supports streaming (no padding required)
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
#ifndef WOLFSSL_USER_SETTINGS
|
|
#include <wolfssl/options.h>
|
|
#endif
|
|
#include <wolfssl/wolfcrypt/settings.h>
|
|
#include <wolfssl/wolfcrypt/aes.h>
|
|
#include <wolfssl/wolfcrypt/random.h>
|
|
#include <wolfssl/wolfcrypt/error-crypt.h>
|
|
|
|
#if !defined(NO_AES) && defined(WOLFSSL_AES_CFB)
|
|
|
|
#define AES_KEY_SIZE AES_256_KEY_SIZE
|
|
|
|
/* Small chunk size to demonstrate streaming */
|
|
#define CHUNK_SIZE 64
|
|
|
|
static int read_file(const char* filename, byte** data, word32* dataSz)
|
|
{
|
|
FILE* fp;
|
|
long fileSz;
|
|
|
|
fp = fopen(filename, "rb");
|
|
if (fp == NULL) {
|
|
printf("Error: Cannot open file %s\n", filename);
|
|
return -1;
|
|
}
|
|
|
|
fseek(fp, 0, SEEK_END);
|
|
fileSz = ftell(fp);
|
|
fseek(fp, 0, SEEK_SET);
|
|
|
|
*data = (byte*)malloc(fileSz);
|
|
if (*data == NULL) {
|
|
fclose(fp);
|
|
printf("Error: Memory allocation failed\n");
|
|
return -1;
|
|
}
|
|
|
|
*dataSz = (word32)fread(*data, 1, fileSz, fp);
|
|
fclose(fp);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int write_file(const char* filename, const byte* data, word32 dataSz)
|
|
{
|
|
FILE* fp;
|
|
|
|
fp = fopen(filename, "wb");
|
|
if (fp == NULL) {
|
|
printf("Error: Cannot create file %s\n", filename);
|
|
return -1;
|
|
}
|
|
|
|
fwrite(data, 1, dataSz, fp);
|
|
fclose(fp);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* One-shot encryption */
|
|
static int encrypt_file(const char* inFile, const char* outFile,
|
|
const byte* key, word32 keySz)
|
|
{
|
|
Aes aes;
|
|
WC_RNG rng;
|
|
byte iv[AES_BLOCK_SIZE];
|
|
byte* plaintext = NULL;
|
|
byte* ciphertext = NULL;
|
|
word32 plaintextSz;
|
|
int ret;
|
|
|
|
ret = read_file(inFile, &plaintext, &plaintextSz);
|
|
if (ret != 0) return ret;
|
|
|
|
/* IV + ciphertext */
|
|
ciphertext = (byte*)malloc(plaintextSz + AES_BLOCK_SIZE);
|
|
if (ciphertext == NULL) {
|
|
free(plaintext);
|
|
return -1;
|
|
}
|
|
|
|
/* Generate random IV */
|
|
ret = wc_InitRng(&rng);
|
|
if (ret != 0) {
|
|
free(plaintext);
|
|
free(ciphertext);
|
|
return ret;
|
|
}
|
|
|
|
ret = wc_RNG_GenerateBlock(&rng, iv, AES_BLOCK_SIZE);
|
|
wc_FreeRng(&rng);
|
|
if (ret != 0) {
|
|
free(plaintext);
|
|
free(ciphertext);
|
|
return ret;
|
|
}
|
|
|
|
/* Initialize AES */
|
|
ret = wc_AesInit(&aes, NULL, INVALID_DEVID);
|
|
if (ret != 0) {
|
|
free(plaintext);
|
|
free(ciphertext);
|
|
return ret;
|
|
}
|
|
|
|
ret = wc_AesSetKey(&aes, key, keySz, iv, AES_ENCRYPTION);
|
|
if (ret != 0) {
|
|
wc_AesFree(&aes);
|
|
free(plaintext);
|
|
free(ciphertext);
|
|
return ret;
|
|
}
|
|
|
|
/* One-shot encrypt */
|
|
ret = wc_AesCfbEncrypt(&aes, ciphertext + AES_BLOCK_SIZE, plaintext,
|
|
plaintextSz);
|
|
wc_AesFree(&aes);
|
|
|
|
if (ret != 0) {
|
|
free(plaintext);
|
|
free(ciphertext);
|
|
return ret;
|
|
}
|
|
|
|
/* Prepend IV to output */
|
|
memcpy(ciphertext, iv, AES_BLOCK_SIZE);
|
|
|
|
ret = write_file(outFile, ciphertext, plaintextSz + AES_BLOCK_SIZE);
|
|
|
|
free(plaintext);
|
|
free(ciphertext);
|
|
|
|
printf("AES-CFB encryption complete (one-shot)\n");
|
|
return ret;
|
|
}
|
|
|
|
/* Streaming decryption - process in chunks */
|
|
static int decrypt_file(const char* inFile, const char* outFile,
|
|
const byte* key, word32 keySz)
|
|
{
|
|
Aes aes;
|
|
byte iv[AES_BLOCK_SIZE];
|
|
byte* ciphertext = NULL;
|
|
byte* plaintext = NULL;
|
|
word32 ciphertextSz;
|
|
word32 plaintextSz;
|
|
word32 offset;
|
|
word32 chunkSz;
|
|
int ret;
|
|
|
|
ret = read_file(inFile, &ciphertext, &ciphertextSz);
|
|
if (ret != 0) return ret;
|
|
|
|
if (ciphertextSz < AES_BLOCK_SIZE) {
|
|
free(ciphertext);
|
|
printf("Error: File too small\n");
|
|
return -1;
|
|
}
|
|
|
|
/* Extract IV from beginning */
|
|
memcpy(iv, ciphertext, AES_BLOCK_SIZE);
|
|
|
|
plaintextSz = ciphertextSz - AES_BLOCK_SIZE;
|
|
plaintext = (byte*)malloc(plaintextSz);
|
|
if (plaintext == NULL) {
|
|
free(ciphertext);
|
|
return -1;
|
|
}
|
|
|
|
/* Initialize AES */
|
|
ret = wc_AesInit(&aes, NULL, INVALID_DEVID);
|
|
if (ret != 0) {
|
|
free(ciphertext);
|
|
free(plaintext);
|
|
return ret;
|
|
}
|
|
|
|
ret = wc_AesSetKey(&aes, key, keySz, iv, AES_ENCRYPTION);
|
|
if (ret != 0) {
|
|
wc_AesFree(&aes);
|
|
free(ciphertext);
|
|
free(plaintext);
|
|
return ret;
|
|
}
|
|
|
|
/* Streaming decrypt - process in chunks */
|
|
printf("AES-CFB streaming decryption:\n");
|
|
offset = 0;
|
|
while (offset < plaintextSz) {
|
|
chunkSz = plaintextSz - offset;
|
|
if (chunkSz > CHUNK_SIZE) {
|
|
chunkSz = CHUNK_SIZE;
|
|
}
|
|
|
|
ret = wc_AesCfbDecrypt(&aes, plaintext + offset,
|
|
ciphertext + AES_BLOCK_SIZE + offset, chunkSz);
|
|
if (ret != 0) {
|
|
wc_AesFree(&aes);
|
|
free(ciphertext);
|
|
free(plaintext);
|
|
return ret;
|
|
}
|
|
|
|
printf(" Decrypted chunk: offset=%u, size=%u\n", offset, chunkSz);
|
|
offset += chunkSz;
|
|
}
|
|
|
|
wc_AesFree(&aes);
|
|
|
|
ret = write_file(outFile, plaintext, plaintextSz);
|
|
|
|
free(ciphertext);
|
|
free(plaintext);
|
|
|
|
printf("AES-CFB decryption complete (streaming)\n");
|
|
return ret;
|
|
}
|
|
|
|
int main(int argc, char** argv)
|
|
{
|
|
byte key[AES_KEY_SIZE];
|
|
int ret;
|
|
|
|
if (argc != 3) {
|
|
printf("Usage: %s <input file> <output file>\n", argv[0]);
|
|
printf("Encrypts input file (one-shot), then decrypts to output file "
|
|
"(streaming)\n");
|
|
return 1;
|
|
}
|
|
|
|
wolfCrypt_Init();
|
|
|
|
/* Use a fixed key for demonstration */
|
|
memset(key, 0x02, AES_KEY_SIZE);
|
|
|
|
/* Encrypt to temporary file */
|
|
ret = encrypt_file(argv[1], "temp_encrypted.bin", key, AES_KEY_SIZE);
|
|
if (ret != 0) {
|
|
printf("Encryption failed: %d\n", ret);
|
|
wolfCrypt_Cleanup();
|
|
return 1;
|
|
}
|
|
|
|
/* Decrypt to output file */
|
|
ret = decrypt_file("temp_encrypted.bin", argv[2], key, AES_KEY_SIZE);
|
|
if (ret != 0) {
|
|
printf("Decryption failed: %d\n", ret);
|
|
wolfCrypt_Cleanup();
|
|
return 1;
|
|
}
|
|
|
|
/* Clean up temp file */
|
|
remove("temp_encrypted.bin");
|
|
|
|
printf("Success! Decrypted file written to %s\n", argv[2]);
|
|
|
|
wolfCrypt_Cleanup();
|
|
return 0;
|
|
}
|
|
|
|
#else
|
|
|
|
int main(int argc, char** argv)
|
|
{
|
|
(void)argc;
|
|
(void)argv;
|
|
printf("AES-CFB not compiled in. Enable with WOLFSSL_AES_CFB\n");
|
|
return 0;
|
|
}
|
|
|
|
#endif
|