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#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include "aes_gcm.h"

#define TXT_SIZE  8
#define AAD_SIZE 32
#define TAG_SIZE 16		/* Valid values are 16, 12, or 8 */
#define KEY_SIZE GCM_256_KEY_LEN
#define IV_SIZE  GCM_IV_DATA_LEN

void mprint(const char *msg, uint8_t * buf, int len)
{
	int i;
	printf("%s", msg);
	for (i = 0; i < len;) {
		printf(" %2x", 0xff & buf[i++]);
		if (i % 32 == 0)
			printf("\n");
	}
	printf("\n");
}

int main(void)
{
	struct gcm_key_data gkey;
	struct gcm_context_data gctx;
	uint8_t ct[TXT_SIZE], pt[TXT_SIZE], pt2[TXT_SIZE];	// Cipher text and plain text
	uint8_t iv[IV_SIZE], aad[AAD_SIZE], key[KEY_SIZE];	// Key and authentication data
	uint8_t tag1[TAG_SIZE], tag2[TAG_SIZE];	// Authentication tags for encode and decode

	printf("gcm example:\n");
	memset(key, 0, KEY_SIZE);
	memset(pt, 0, TXT_SIZE);
	memset(iv, 0, IV_SIZE);
	memset(aad, 0, AAD_SIZE);

	aes_gcm_pre_256(key, &gkey);
	aes_gcm_enc_256(&gkey, &gctx, ct, pt, TXT_SIZE, iv, aad, AAD_SIZE, tag1, TAG_SIZE);
	aes_gcm_dec_256(&gkey, &gctx, pt2, ct, TXT_SIZE, iv, aad, AAD_SIZE, tag2, TAG_SIZE);

	mprint("  input text:     ", pt, TXT_SIZE);
	mprint("  cipher text:    ", ct, TXT_SIZE);
	mprint("  decode text:    ", pt2, TXT_SIZE);
	mprint("  ath tag1 (enc): ", tag1, TAG_SIZE);
	mprint("  ath tag2 (dec): ", tag2, TAG_SIZE);

	return memcmp(tag1, tag2, TAG_SIZE);
}