The supported board list:
- SAM L21 Xplained Pro
- SAM L22 Xplained Pro
This example demonstrates how to use the AES driver to perform:
- ECB encryption and decryption
Upon startup, the program uses the USART driver to display application output message from which ECB encryption/decryption modes can be tested.
Quick Start
Prerequisites
There are no prerequisites for this use case.
Code
Add to the main application source file, outside of any functions:
#define AES_EXAMPLE_REFBUF_SIZE 4
uint32_t ref_plain_text[AES_EXAMPLE_REFBUF_SIZE] = {
0xe2bec16b,
0x969f402e,
0x117e3de9,
0x2a179373
};
uint32_t ref_cipher_text_ecb[AES_EXAMPLE_REFBUF_SIZE] = {
0xb47bd73a,
0x60367a0d,
0xf3ca9ea8,
0x97ef6624
};
const uint32_t key128[4] = {
0x16157e2b,
0xa6d2ae28,
0x8815f7ab,
0x3c4fcf09
};
Add to the main application source file, outside of any functions:
static uint32_t output_data[AES_EXAMPLE_REFBUF_SIZE];
volatile bool state = false;
struct aes_module aes_instance;
Copy-paste the following setup code to your user application:
static void configure_usart(void)
{
config_usart.baudrate = 38400;
config_usart.mux_setting = EDBG_CDC_SERCOM_MUX_SETTING;
config_usart.pinmux_pad0 = EDBG_CDC_SERCOM_PINMUX_PAD0;
config_usart.pinmux_pad1 = EDBG_CDC_SERCOM_PINMUX_PAD1;
config_usart.pinmux_pad2 = EDBG_CDC_SERCOM_PINMUX_PAD2;
config_usart.pinmux_pad3 = EDBG_CDC_SERCOM_PINMUX_PAD3;
stdio_serial_init(&usart_instance, EDBG_CDC_MODULE, &config_usart);
}
static void ecb_mode_test(void)
{
printf("\r\n-----------------------------------\r\n");
printf("- 128bit cryptographic key\r\n");
printf("- ECB cipher mode\r\n");
printf("- Auto start mode\r\n");
printf("- 4 32bit words\r\n");
printf("-----------------------------------\r\n");
state = false;
g_aes_cfg.lod = false;
}
if ((ref_cipher_text_ecb[0] != output_data[0]) ||
(ref_cipher_text_ecb[1] != output_data[1]) ||
(ref_cipher_text_ecb[2] != output_data[2]) ||
(ref_cipher_text_ecb[3] != output_data[3])) {
printf("\r\nKO!!!\r\n");
} else {
printf("\r\nOK!!!\r\n");
}
printf("\r\n-----------------------------------\r\n");
printf("- 128bit cryptographic key\r\n");
printf("- ECB decipher mode\r\n");
printf("- Auto start mode\r\n");
printf("- 4 32bit words\r\n");
printf("-----------------------------------\r\n");
state = false;
g_aes_cfg.lod = false;
}
if ((ref_plain_text[0] != output_data[0]) ||
(ref_plain_text[1] != output_data[1]) ||
(ref_plain_text[2] != output_data[2]) ||
(ref_plain_text[3] != output_data[3])) {
printf("\r\nKO!!!\r\n");
} else {
printf("\r\nOK!!!\r\n");
}
}
Add to user application initialization (typically the start of main()
):
configure_usart();
aes_init(&aes_instance,AES, &g_aes_cfg);
Workflow
- Define sample data from NIST-800-38A appendix F for ECB mode.
#define AES_EXAMPLE_REFBUF_SIZE 4
uint32_t ref_plain_text[AES_EXAMPLE_REFBUF_SIZE] = {
0xe2bec16b,
0x969f402e,
0x117e3de9,
0x2a179373
};
uint32_t ref_cipher_text_ecb[AES_EXAMPLE_REFBUF_SIZE] = {
0xb47bd73a,
0x60367a0d,
0xf3ca9ea8,
0x97ef6624
};
const uint32_t key128[4] = {
0x16157e2b,
0xa6d2ae28,
0x8815f7ab,
0x3c4fcf09
};
- Create related module variable and software instance structure.
static uint32_t output_data[AES_EXAMPLE_REFBUF_SIZE];
volatile bool state = false;
struct aes_module aes_instance;
- Configure, initialize, and enable AES module.
- Configuration AES struct, which can be filled out to adjust the configuration of a physical AES peripheral.
- Initialize the AES configuration struct with the module's default values.
aes_init(&aes_instance,AES, &g_aes_cfg);
- Enable the AES module.
Use Case
Code
Copy-paste the following code to your user application:
Workflow
- Configure ECB mode encryption and run test.
state = false;
g_aes_cfg.lod = false;
}
if ((ref_cipher_text_ecb[0] != output_data[0]) ||
(ref_cipher_text_ecb[1] != output_data[1]) ||
(ref_cipher_text_ecb[2] != output_data[2]) ||
(ref_cipher_text_ecb[3] != output_data[3])) {
printf("\r\nKO!!!\r\n");
} else {
printf("\r\nOK!!!\r\n");
}
- Configure ECB mode decryption and run test.
state = false;
g_aes_cfg.lod = false;
}
if ((ref_plain_text[0] != output_data[0]) ||
(ref_plain_text[1] != output_data[1]) ||
(ref_plain_text[2] != output_data[2]) ||
(ref_plain_text[3] != output_data[3])) {
printf("\r\nKO!!!\r\n");
} else {
printf("\r\nOK!!!\r\n");
}