Low-level crypto API for an AES unit implemented in AT86RF2xx.

#include "trx_access.h"
#include "sal_types.h"
#include <string.h>
#include "sal.h"
#include "delay.h"

Macros
#define	_SR_MASK(addr, mask, pos, val) (((uint8_t)val << pos) & mask)

#define	AES_DIR_VOID (AES_DIR_ENCRYPT + AES_DIR_DECRYPT + 1)

#define	AES_RY_BIT (1) /* AES_RY: poll on finished op */

#define	SR_MASK(SR, val) _SR_MASK(SR, val)

Functions
void	_sal_aes_clean_up (void)
	Cleans up the SAL/AES after STB has been finished. More...

void	sal_aes_read (uint8_t *data)
	Reads the result of previous AES en/decryption. More...

void	sal_aes_restart (void)
	Re-inits key and state after a sleep or TRX reset. More...

bool	sal_aes_setup (uint8_t *key, uint8_t enc_mode, uint8_t dir)
	Setup AES unit. More...

void	sal_aes_wrrd (uint8_t idata, uint8_t odata)
	Writes data, reads previous result and does the AES en/decryption. More...

void	sal_init (void)
	Initialization of SAL. More...

Variables
static uint8_t	aes_buf [AES_BLOCKSIZE+2]

static bool	dec_initialized = false

static uint8_t	dec_key [AES_KEYSIZE]

static uint8_t	enc_key [AES_KEYSIZE]

static uint8_t	last_dir = AES_DIR_VOID

static bool	setup_flag

#define _SR_MASK	(	addr,
		mask,
		pos,
		val
	)	(((uint8_t)val << pos) & mask)

#define AES_DIR_VOID (AES_DIR_ENCRYPT + AES_DIR_DECRYPT + 1)

Referenced by sal_aes_setup().

#define AES_RY_BIT (1) /* AES_RY: poll on finished op */

Author: Microchip Technology Inc: http://www.microchip.com Support: https://www.microchip.com/support/

#define SR_MASK	(	SR,
		val
	)	_SR_MASK(SR, val)

Referenced by sal_aes_restart(), and sal_aes_setup().

void _sal_aes_clean_up ( void )

Cleans up the SAL/AES after STB has been finished.

Cleans up the SAL/AES after STB has been completed.

void sal_aes_read ( uint8_t * data )

Reads the result of previous AES en/decryption.

This function returns the result of the previous AES operation, so this function is needed in order to get the last result of a series of sal_aes_wrrd() calls.

Parameters

[out] data - result of previous operation

References AES_BASE_ADDR, AES_BLOCKSIZE, RG_AES_STATE_KEY_0, and trx_sram_read().

Referenced by compute_mic(), and encrypt_pldmic().

void sal_aes_restart ( void )

Re-inits key and state after a sleep or TRX reset.

This function re-initializes the AES key and the state of the AES engine after TRX sleep or reset. The contents of AES registers AES_CON and AES_CON_MIRROR are restored, the next AES operation started with sal_aes_wrrd() will be executed correctly. However, the contents of SRAM buffers is destroyed, in general. When using sal_aes_wrrd(), call sal_aes_read() to get the result of the last AES operation BEFORE you put the transceiver unit to sleep state!

References AES_BASE_ADDR, AES_BLOCKSIZE, aes_buf, AES_DIR_ENCRYPT, AES_KEYSIZE, AES_MODE_KEY, dec_key, enc_key, last_dir, RG_AES_CTRL, setup_flag, SR_AES_MODE, SR_MASK, and trx_sram_write().

Referenced by stb_ccm_secure().

bool sal_aes_setup	(	uint8_t *	key,
		uint8_t	enc_mode,
		uint8_t	dir
	)

Setup AES unit.

This function perform the following tasks as part of the setup of the AES unit: key initialization, set encryption direction and encryption mode.

In general, the contents of SRAM buffer is destroyed. When using sal_aes_wrrd(), sal_aes_read() needs to be called in order to get the result of the last AES operation before you may call sal_aes_setup() again.

Parameters

[in]	key	AES key or NULL (NULL: use last key)
[in]	enc_mode	AES_MODE_ECB or AES_MODE_CBC
[in]	dir	AES_DIR_ENCRYPT or AES_DIR_DECRYPT

Returns: False if some parameter was illegal, true else

References AES_BASE_ADDR, AES_BLOCKSIZE, aes_buf, AES_DIR_DECRYPT, AES_DIR_ENCRYPT, AES_DIR_VOID, AES_KEYSIZE, AES_MODE_CBC, AES_MODE_ECB, AES_MODE_KEY, AES_REQUEST, dec_initialized, dec_key, enc_key, last_dir, RG_AES_CTRL, RG_AES_STATE_KEY_0, sal_aes_wrrd(), setup_flag, SR_AES_DIR, SR_AES_MODE, SR_AES_REQUEST, SR_MASK, trx_sram_read(), and trx_sram_write().

Referenced by compute_mic(), encrypt_pldmic(), and stb_ccm_secure().

void sal_aes_wrrd	(	uint8_t *	idata,
		uint8_t *	odata
	)

Writes data, reads previous result and does the AES en/decryption.

The function returns after the AES operation is finished.

When sal_aes_wrrd() is called several times in sequence, from the second call onwards, odata contains the result of the previous operation. To obtain the last result, you must call sal_aes_read() at the end. Please note that any call of sal_aes_setup() as well as putting the transceiver to sleep state destroys the SRAM contents, i.e. the next call of sal_aes_wrrd() yields no meaningful result.

Parameters