embedtls (polarssl) aes gcm sample

polarssl_gcm.c

void test3()
{
	int ret;

	const uint8_t key[16] = { 0xfe, 0x03, 0xcc, 0x7e, 0x7a, 0x59, 0x4a, 0x82, 0x6c, 0x3e, 0x1d, 0xec, 0x26, 0x5d, 0xdd, 0xcf };
	const uint8_t iv[16] = { 0x3a, 0x1d, 0x70, 0x5c, 0xb0, 0xed, 0xa3, 0xad, 0xdd, 0xe8, 0x3d, 0x4b, 0x48, 0xeb, 0x26, 0xe2 };
	const size_t iv_len = 12;  // в тестах есть значения 12, 12, 12, 12, 8, 60
	const uint8_t add_data[3] = { 42, 43, 44 };
	const size_t add_data_len = 2;

	uint8_t input_data[32];
	for (int i = 0; i < 32; ++i)
	input_data[i] = i;

	const size_t dataLen = 30;

	uint8_t encrypted_data[32] = { 0 };
	uint8_t decrypted_data[32] = { 0 };
	uint8_t tag_buffer[16] = { 0 };
	uint8_t tag_buffer_enc[16] = { 0 };

	const size_t tagLen = 8;

	mbedtls_gcm_context ctx;

	// ENCRYPT

	mbedtls_gcm_init(&ctx);

	ret = mbedtls_gcm_setkey(&ctx, MBEDTLS_CIPHER_ID_AES, key, 128);
	//assert(ret == 0);

	ret = mbedtls_gcm_crypt_and_tag(&ctx,       // context
	MBEDTLS_GCM_ENCRYPT,                    // mode
	dataLen,                                // length
	iv,                                     // iv
	iv_len,                                 // iv len
	add_data,                               // additional data
	add_data_len,                           // additional data len
	input_data,                             // plain data
	encrypted_data,                         // output
	tagLen,                                 // tag len
	tag_buffer);                            // tag buffer
	//assert(ret == 0);

	mbedtls_gcm_free(&ctx);



	//encrypted_data[5] = 0xf0; // corrupt data


	// DECRYPT

	mbedtls_gcm_init(&ctx);

	ret = mbedtls_gcm_setkey(&ctx, MBEDTLS_CIPHER_ID_AES, key, 128);
	//assert(ret == 0);

	ret = mbedtls_gcm_auth_decrypt(&ctx,         // context
	dataLen,                                // length
	iv,                                     // iv
	iv_len,                                 // iv len
	add_data,                               // additional data
	add_data_len,                           // 3
	tag_buffer,                             // orig tag
	tagLen,                                 // tag len
	encrypted_data,                         // inputt
	decrypted_data                          // output
	);

	//assert(ret == 0);

	mbedtls_gcm_free(&ctx);
}