AES-GCM one shot example

Add a simple example of using the AES-GCM oneshot API for encryption and
decryption.

Author: SparkiDev

.gitignore

@@ -118,6 +118,8 @@ crypto/3des/3des-file-encrypt
 crypto/aes/aes-file-encrypt
 crypto/aes/aescfb-file-encrypt
 crypto/aes/aesctr-file-encrypt
+crypto/aes/aesgcm-file-encrypt
+crypto/aes/aesgcm-oneshot
 crypto/camellia/camellia-encrypt
 crypto/pkcs12/pkcs12-create-example
 crypto/pkcs12/pkcs12-example

crypto/aes/Makefile

@@ -3,7 +3,7 @@ CFLAGS=-Wall
 WOLFSSL_INSTALL_DIR=/usr/local
 LIBS=-L$(WOLFSSL_INSTALL_DIR)/lib -lwolfssl -lm
 
-all: aes-file-encrypt aescfb-file-encrypt aesctr-file-encrypt aesgcm-file-encrypt
+all: aes-file-encrypt aescfb-file-encrypt aesctr-file-encrypt aesgcm-file-encrypt aesgcm-oneshot
 
 aes-file-encrypt: aes-file-encrypt.o
 	$(CC) -o $@ $^ $(CFLAGS) $(LIBS) 
@@ -17,7 +17,10 @@ aesctr-file-encrypt: aesctr-file-encrypt.o
 aesgcm-file-encrypt: aesgcm-file-encrypt.o
 	$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
 
+aesgcm-oneshot: aesgcm-oneshot.o
+	$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
+
 .PHONY: clean
 
 clean:
-	rm -f *.o aes-file-encrypt aescfb-file-encrypt aesctr-file-encrypt aesgcm-file-encrypt text*
+	rm -f *.o aes-file-encrypt aescfb-file-encrypt aesctr-file-encrypt aesgcm-file-encrypt text* aesgcm-oneshot

crypto/aes/aesgcm-oneshot.c

@@ -0,0 +1,142 @@
+/* aesgcm-oneshot.c
+ *
+ * Copyright (C) 2006-2024 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
+ */
+
+
+#include <wolfssl/options.h>
+#include <wolfssl/wolfcrypt/settings.h>
+#include <wolfssl/wolfcrypt/error-crypt.h>
+#include <wolfssl/wolfcrypt/logging.h>
+#include <wolfssl/wolfcrypt/aes.h>
+
+#if !defined(NO_AES) && defined(HAVE_AESGCM)
+int aesgcm_enc_dec()
+{
+    Aes           aesEnc;
+    Aes           aesDec;
+    unsigned char key[AES_256_KEY_SIZE];
+    int           ret = 0;
+    unsigned char data[33];
+    unsigned char enc[33];
+    unsigned char dec[33];
+    unsigned char iv[GCM_NONCE_MID_SZ];
+    unsigned char authTag[AES_BLOCK_SIZE];
+    size_t        i;
+
+    memset(key, 9, sizeof(key));
+    memset(data, 9, sizeof(data));
+    memset(iv, 9, sizeof(iv));
+
+    fprintf(stderr, "Encrypt with AES128-GCM\n");
+    /* Initialize AES encryption object. */
+    ret = wc_AesInit(&aesEnc, NULL, INVALID_DEVID);
+    if (ret == 0) {
+        /* Set GCM key into AES encryption object. */
+        ret = wc_AesGcmSetKey(&aesEnc, key, AES_128_KEY_SIZE);
+        if (ret != 0)
+            fprintf(stderr, "Set Key failed: %d\n", ret);
+    }
+    if (ret == 0) {
+        printf(" Plaintext: ");
+        for (i = 0; i < sizeof(data); i++)
+            printf("%02x", data[i]);
+        printf("\n");
+
+        /* Encrypt data with AES encryption object and get ciphertext and
+         * authentication tag. No additional authentication data. */
+        ret = wc_AesGcmEncrypt(&aesEnc, enc, data, sizeof(data), iv, sizeof(iv),
+                               authTag, sizeof(authTag), NULL, 0);
+        if (ret != 0)
+            fprintf(stderr, "Encrypt failed: %d\n", ret);
+    }
+    if (ret == 0) {
+        printf("Ciphertext: ");
+        for (i = 0; i < sizeof(data); i++)
+            printf("%02x", enc[i]);
+        printf("\n");
+        printf("  Auth Tag: ");
+        for (i = 0; i < sizeof(authTag); i++)
+            printf("%02x", authTag[i]);
+        printf("\n");
+    }
+
+    if (ret == 0) {
+        fprintf(stderr, "Decrypt with AES128-GCM\n");
+        /* Initialize AES decryption object. */
+        ret = wc_AesInit(&aesDec, NULL, INVALID_DEVID);
+    }
+    if (ret == 0) {
+        /* Set GCM key into AES decryption object. */
+        ret = wc_AesGcmSetKey(&aesDec, key, AES_128_KEY_SIZE);
+        if (ret != 0)
+            fprintf(stderr, "Set Key failed: %d\n", ret);
+    }
+    if (ret == 0) {
+        /* Check authentication tag with ciphertext and decrypt ciphertext with
+         * AES decryption object and get decrypted data. No additional
+         * authentication data. */
+        ret = wc_AesGcmDecrypt(&aesDec, dec, enc, sizeof(enc), iv, sizeof(iv),
+                               authTag, sizeof(authTag), NULL, 0);
+        if (ret == AES_GCM_AUTH_E)
+            fprintf(stderr, "Authentication failed: %d\n", ret);
+        else if (ret != 0)
+            fprintf(stderr, "Decrypt failed: %d\n", ret);
+    }
+    if (ret == 0) {
+        printf(" Decrypted: ");
+        for (i = 0; i < sizeof(data); i++)
+            printf("%02x", dec[i]);
+        printf("\n");
+    }
+
+    return ret;
+}
+#endif
+
+int main(int argc, char* argv[])
+{
+    int ret = 0;
+
+    if (argc != 1) {
+        fprintf(stderr, "Usage: %s\n", argv[0]);
+        return 1;
+    }
+
+#if !defined(NO_AES) && defined(HAVE_AESGCM)
+
+#if defined(DEBUG_WOLFSSL)
+    wolfSSL_Debugging_ON();
+#endif
+    wolfCrypt_Init();
+
+    if (aesgcm_enc_dec() != 0)
+        ret = 1;
+
+    wolfCrypt_Cleanup();
+
+#else
+
+    printf("AES-GCM not built into wolfSSL\n");
+
+#endif
+
+    return ret;
+}
+