WolfSSL
/
wolfssl-examples
mirror of https://github.com/wolfSSL/wolfssl-examples.git
1
0
Fork 0
Code Issues Releases Wiki Activity

Merge pull request #548 from anhu/aes_modes_gcm_gmac 

AES modes extravaganza. gcm and gmac
pull/552/head
JacobBarthelmeh 2025-12-18 16:46:51 -07:00 committed by GitHub
parent 1b5089b5cf e6fb240e62
commit 13282ceb6b
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
2 changed files with 685 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

406
crypto/aes-modes/aes-gcm.c 100644
View File

@ -0,0 +1,406 @@
/* aes-gcm.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-GCM Example
* This example demonstrates:
* - One-shot encryption using wc_AesGcmEncrypt()
* - Streaming decryption using wc_AesGcmDecryptInit/Update/Final()
* Note: GCM provides authenticated encryption (AEAD)
*/
#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(HAVE_AESGCM)
#define AES_KEY_SIZE AES_256_KEY_SIZE
#define GCM_IV_SIZE 12 /* Recommended IV size for GCM */
#define GCM_TAG_SIZE 16 /* Authentication tag size */
#define CHUNK_SIZE 64 /* Small chunk size to demonstrate streaming */
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[GCM_IV_SIZE];
byte authTag[GCM_TAG_SIZE];
byte* plaintext = NULL;
byte* output = NULL;
word32 plaintextSz;
word32 outputSz;
int ret;
ret = read_file(inFile, &plaintext, &plaintextSz);
if (ret != 0) return ret;
/* Output: IV + authTag + ciphertext */
outputSz = GCM_IV_SIZE + GCM_TAG_SIZE + plaintextSz;
output = (byte*)malloc(outputSz);
if (output == NULL) {
free(plaintext);
return -1;
}
/* Generate random IV */
ret = wc_InitRng(&rng);
if (ret != 0) {
free(plaintext);
free(output);
return ret;
}
ret = wc_RNG_GenerateBlock(&rng, iv, GCM_IV_SIZE);
wc_FreeRng(&rng);
if (ret != 0) {
free(plaintext);
free(output);
return ret;
}
/* Initialize AES-GCM */
ret = wc_AesInit(&aes, NULL, INVALID_DEVID);
if (ret != 0) {
free(plaintext);
free(output);
return ret;
}
ret = wc_AesGcmSetKey(&aes, key, keySz);
if (ret != 0) {
wc_AesFree(&aes);
free(plaintext);
free(output);
return ret;
}
/* One-shot encrypt with authentication */
ret = wc_AesGcmEncrypt(&aes, output + GCM_IV_SIZE + GCM_TAG_SIZE,
plaintext, plaintextSz,
iv, GCM_IV_SIZE,
authTag, GCM_TAG_SIZE,
NULL, 0); /* No additional authenticated data */
wc_AesFree(&aes);
if (ret != 0) {
free(plaintext);
free(output);
return ret;
}
/* Prepend IV and authTag to output */
memcpy(output, iv, GCM_IV_SIZE);
memcpy(output + GCM_IV_SIZE, authTag, GCM_TAG_SIZE);
ret = write_file(outFile, output, outputSz);
free(plaintext);
free(output);
printf("AES-GCM encryption complete (one-shot)\n");
return ret;
}
#ifdef WOLFSSL_AESGCM_STREAM
/* Streaming decryption using Init/Update/Final API */
static int decrypt_file(const char* inFile, const char* outFile,
const byte* key, word32 keySz)
{
Aes aes;
byte iv[GCM_IV_SIZE];
byte authTag[GCM_TAG_SIZE];
byte* input = NULL;
byte* plaintext = NULL;
word32 inputSz;
word32 ciphertextSz;
word32 offset;
word32 chunkSz;
int ret;
ret = read_file(inFile, &input, &inputSz);
if (ret != 0) return ret;
if (inputSz < GCM_IV_SIZE + GCM_TAG_SIZE) {
free(input);
printf("Error: File too small\n");
return -1;
}
/* Extract IV and authTag from beginning */
memcpy(iv, input, GCM_IV_SIZE);
memcpy(authTag, input + GCM_IV_SIZE, GCM_TAG_SIZE);
ciphertextSz = inputSz - GCM_IV_SIZE - GCM_TAG_SIZE;
plaintext = (byte*)malloc(ciphertextSz);
if (plaintext == NULL) {
free(input);
return -1;
}
/* Initialize AES-GCM for streaming decryption */
ret = wc_AesInit(&aes, NULL, INVALID_DEVID);
if (ret != 0) {
free(input);
free(plaintext);
return ret;
}
ret = wc_AesGcmDecryptInit(&aes, key, keySz, iv, GCM_IV_SIZE);
if (ret != 0) {
wc_AesFree(&aes);
free(input);
free(plaintext);
return ret;
}
/* Streaming decrypt - process in chunks */
printf("AES-GCM streaming decryption:\n");
offset = 0;
while (offset < ciphertextSz) {
chunkSz = ciphertextSz - offset;
if (chunkSz > CHUNK_SIZE) {
chunkSz = CHUNK_SIZE;
}
ret = wc_AesGcmDecryptUpdate(&aes, plaintext + offset,
input + GCM_IV_SIZE + GCM_TAG_SIZE + offset,
chunkSz, NULL, 0);
if (ret != 0) {
wc_AesFree(&aes);
free(input);
free(plaintext);
return ret;
}
printf(" Decrypted chunk: offset=%u, size=%u\n", offset, chunkSz);
offset += chunkSz;
}
/* Finalize and verify authentication tag */
ret = wc_AesGcmDecryptFinal(&aes, authTag, GCM_TAG_SIZE);
wc_AesFree(&aes);
if (ret != 0) {
free(input);
free(plaintext);
if (ret == AES_GCM_AUTH_E) {
printf("Error: Authentication failed!\n");
}
return ret;
}
ret = write_file(outFile, plaintext, ciphertextSz);
free(input);
free(plaintext);
printf("AES-GCM decryption complete (streaming) - authentication "
"verified\n");
return ret;
}
#else
/* Fallback: One-shot decryption when streaming not available */
static int decrypt_file(const char* inFile, const char* outFile,
const byte* key, word32 keySz)
{
Aes aes;
byte iv[GCM_IV_SIZE];
byte authTag[GCM_TAG_SIZE];
byte* input = NULL;
byte* plaintext = NULL;
word32 inputSz;
word32 ciphertextSz;
int ret;
ret = read_file(inFile, &input, &inputSz);
if (ret != 0) return ret;
if (inputSz < GCM_IV_SIZE + GCM_TAG_SIZE) {
free(input);
printf("Error: File too small\n");
return -1;
}
/* Extract IV and authTag from beginning */
memcpy(iv, input, GCM_IV_SIZE);
memcpy(authTag, input + GCM_IV_SIZE, GCM_TAG_SIZE);
ciphertextSz = inputSz - GCM_IV_SIZE - GCM_TAG_SIZE;
plaintext = (byte*)malloc(ciphertextSz);
if (plaintext == NULL) {
free(input);
return -1;
}
/* Initialize AES-GCM */
ret = wc_AesInit(&aes, NULL, INVALID_DEVID);
if (ret != 0) {
free(input);
free(plaintext);
return ret;
}
ret = wc_AesGcmSetKey(&aes, key, keySz);
if (ret != 0) {
wc_AesFree(&aes);
free(input);
free(plaintext);
return ret;
}
/* One-shot decrypt with authentication verification */
ret = wc_AesGcmDecrypt(&aes, plaintext,
input + GCM_IV_SIZE + GCM_TAG_SIZE, ciphertextSz,
iv, GCM_IV_SIZE,
authTag, GCM_TAG_SIZE,
NULL, 0);
wc_AesFree(&aes);
if (ret != 0) {
free(input);
free(plaintext);
if (ret == AES_GCM_AUTH_E) {
printf("Error: Authentication failed!\n");
}
return ret;
}
ret = write_file(outFile, plaintext, ciphertextSz);
free(input);
free(plaintext);
printf("AES-GCM decryption complete (one-shot, streaming not available)\n");
return ret;
}
#endif /* WOLFSSL_AESGCM_STREAM */
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\n");
#ifdef WOLFSSL_AESGCM_STREAM
printf("Streaming decryption enabled\n");
#else
printf("Streaming decryption not available (enable WOLFSSL_AESGCM_STREAM)\n");
#endif
return 1;
}
wolfCrypt_Init();
/* Use a fixed key for demonstration */
memset(key, 0x09, 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-GCM not compiled in. Enable with HAVE_AESGCM\n");
return 0;
}
#endif

279
crypto/aes-modes/aes-gmac.c 100644
View File

@ -0,0 +1,279 @@
/* aes-gmac.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-GMAC Example
* This example demonstrates:
* - One-shot authentication using wc_GmacUpdate() to generate auth tag
* - One-shot verification using wc_GmacVerify()
* Note: GMAC is authentication-only (no encryption), no streaming API
* It authenticates data without encrypting it
*/
#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(HAVE_AESGCM)
#define AES_KEY_SIZE AES_256_KEY_SIZE
#define GMAC_IV_SIZE 12 /* Recommended IV size */
#define GMAC_TAG_SIZE 16 /* Authentication tag size */
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 authentication - generate auth tag for file */
static int authenticate_file(const char* inFile, const char* outFile,
const byte* key, word32 keySz)
{
Gmac gmac;
WC_RNG rng;
byte iv[GMAC_IV_SIZE];
byte authTag[GMAC_TAG_SIZE];
byte* data = NULL;
byte* output = NULL;
word32 dataSz;
word32 outputSz;
int ret;
ret = read_file(inFile, &data, &dataSz);
if (ret != 0) return ret;
/* Output: IV + authTag + original data (unencrypted) */
outputSz = GMAC_IV_SIZE + GMAC_TAG_SIZE + dataSz;
output = (byte*)malloc(outputSz);
if (output == NULL) {
free(data);
return -1;
}
/* Generate random IV */
ret = wc_InitRng(&rng);
if (ret != 0) {
free(data);
free(output);
return ret;
}
ret = wc_RNG_GenerateBlock(&rng, iv, GMAC_IV_SIZE);
wc_FreeRng(&rng);
if (ret != 0) {
free(data);
free(output);
return ret;
}
/* Initialize GMAC */
ret = wc_AesInit(&gmac.aes, NULL, INVALID_DEVID);
if (ret != 0) {
free(data);
free(output);
return ret;
}
ret = wc_GmacSetKey(&gmac, key, keySz);
if (ret != 0) {
wc_AesFree(&gmac.aes);
free(data);
free(output);
return ret;
}
/* One-shot generate authentication tag */
ret = wc_GmacUpdate(&gmac, iv, GMAC_IV_SIZE, data, dataSz,
authTag, GMAC_TAG_SIZE);
wc_AesFree(&gmac.aes);
if (ret != 0) {
free(data);
free(output);
return ret;
}
/* Store IV + authTag + data */
memcpy(output, iv, GMAC_IV_SIZE);
memcpy(output + GMAC_IV_SIZE, authTag, GMAC_TAG_SIZE);
memcpy(output + GMAC_IV_SIZE + GMAC_TAG_SIZE, data, dataSz);
ret = write_file(outFile, output, outputSz);
free(data);
free(output);
printf("AES-GMAC authentication complete (one-shot)\n");
printf(" Generated %d-byte authentication tag\n", GMAC_TAG_SIZE);
return ret;
}
/* One-shot verification - verify auth tag and extract data */
static int verify_file(const char* inFile, const char* outFile,
const byte* key, word32 keySz)
{
byte iv[GMAC_IV_SIZE];
byte authTag[GMAC_TAG_SIZE];
byte* input = NULL;
byte* data = NULL;
word32 inputSz;
word32 dataSz;
int ret;
ret = read_file(inFile, &input, &inputSz);
if (ret != 0) return ret;
if (inputSz < GMAC_IV_SIZE + GMAC_TAG_SIZE) {
free(input);
printf("Error: File too small\n");
return -1;
}
/* Extract IV and authTag from beginning */
memcpy(iv, input, GMAC_IV_SIZE);
memcpy(authTag, input + GMAC_IV_SIZE, GMAC_TAG_SIZE);
dataSz = inputSz - GMAC_IV_SIZE - GMAC_TAG_SIZE;
data = input + GMAC_IV_SIZE + GMAC_TAG_SIZE;
/* One-shot verify authentication tag */
ret = wc_GmacVerify(key, keySz, iv, GMAC_IV_SIZE,
data, dataSz, authTag, GMAC_TAG_SIZE);
if (ret != 0) {
free(input);
if (ret == AES_GCM_AUTH_E) {
printf("Error: Authentication failed! Data may have been "
"tampered with.\n");
}
return ret;
}
/* Write verified data to output */
ret = write_file(outFile, data, dataSz);
free(input);
printf("AES-GMAC verification complete (one-shot)\n");
printf(" Authentication tag verified successfully\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("Authenticates input file (one-shot), then verifies to output "
"file\n");
printf("Note: GMAC provides authentication only, no encryption\n");
return 1;
}
wolfCrypt_Init();
/* Use a fixed key for demonstration */
memset(key, 0x0A, AES_KEY_SIZE);
/* Authenticate to temporary file */
ret = authenticate_file(argv[1], "temp_authenticated.bin", key, AES_KEY_SIZE);
if (ret != 0) {
printf("Authentication failed: %d\n", ret);
wolfCrypt_Cleanup();
return 1;
}
/* Verify and extract to output file */
ret = verify_file("temp_authenticated.bin", argv[2], key, AES_KEY_SIZE);
if (ret != 0) {
printf("Verification failed: %d\n", ret);
wolfCrypt_Cleanup();
return 1;
}
/* Clean up temp file */
remove("temp_authenticated.bin");
printf("Success! Verified file written to %s\n", argv[2]);
wolfCrypt_Cleanup();
return 0;
}
#else
int main(int argc, char** argv)
{
(void)argc;
(void)argv;
printf("AES-GMAC not compiled in. Enable with HAVE_AESGCM\n");
return 0;
}
#endif