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AES128 HW crypto engine support for Atmel radios

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modified:   cpu/avr/radio/rf230bb/atmega128rfa1_registermap.h
modified:   cpu/avr/radio/rf230bb/atmega256rfr2_registermap.h
modified:   cpu/avr/radio/rf230bb/rf230bb.c
modified:   cpu/avr/radio/rf230bb/rf230bb.h
This commit is contained in:
Robert Olsson 2017-04-24 14:34:01 +02:00
parent ddf723f88d
commit 58517dfcbd
4 changed files with 217 additions and 0 deletions
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180
cpu/avr/radio/rf230bb/rf230bb.c
View file

@ -46,6 +46,7 @@
#if defined(__AVR__)
#include <avr/io.h>
#include <dev/watchdog.h>
//_delay_us has the potential to use floating point which brings the 256 byte clz table into RAM
//#include <util/delay.h>
@ -2075,4 +2076,183 @@ void rf230_start_sneeze(void) {
// while (hal_register_read(0x0f)!=1) {continue;} //wait for pll lock-hangs
hal_register_write(0x02,0x02); //Set TRX_STATE to TX_START
}
#endif
#ifdef AES_128_HW_CONF
#define IEEE_VECT 0
extern unsigned char aes_key[16];
extern unsigned char aes_p[];
extern unsigned char aes_c[];
extern unsigned char aes_s[];
extern unsigned char tmp[16];
/*
After PWR_SAVE sleep key is lost. We'll lock en/decyption to avoid
not to forced in to sleep while doing crypto. Also the key is hold
be the user so AES block should be reentrant. Encode/Docode och 128bit
(16 bytes) is promised to be less than 24us.
Note! Radio must be on to use the HW crypto engine. --ro
*/
static void
rf230_aes_write_key(unsigned char *key)
{
uint8_t i;
for(i = 0; i < 16; i++) {
hal_subregister_write(SR_AES_KEY, key[i]);
}
}
static void
rf230_aes_read_key(unsigned char *key)
{
uint8_t i;
for(i = 0; i < 16; i++) {
key[i] = hal_subregister_read(SR_AES_KEY);
}
}
static void
rf230_aes_write_state(unsigned char *state)
{
uint8_t i;
for(i = 0; i < 16; i++) {
hal_subregister_write(SR_AES_STATE, state[i]);
}
}
static void
rf230_aes_read_state(unsigned char *state)
{
uint8_t i;
for(i = 0; i < 16; i++) {
state[i] = hal_subregister_read(SR_AES_STATE);
}
}
static int
crypt(void)
{
uint8_t status;
hal_subregister_write(SR_AES_CNTRL_REQUEST, 1); /* Kick */
do {
watchdog_periodic();
status = hal_subregister_read(SR_AES_STATUS);
} while(status == 0);
if (hal_subregister_read(SR_AES_STATUS_ERR)) {
PRINTF("AES ERR\n");
return 0;
}
if (hal_subregister_read(SR_AES_STATUS_DONE)) {
PRINTF("AES DONE\n");
return 1;
}
return 0; /* Unknown */
}
int
rf230_aes_encrypt_cbc(unsigned char *key, unsigned char *plain, int len, unsigned char *mic)
{
uint8_t i;
uint8_t sreg;
int res;
sreg = SREG;
cli();
rf230_aes_write_key(key);
hal_subregister_write(SR_AES_CNTRL_MODE, 0); /* AES_MODE=0 -> ECB for 1:st block*/
hal_subregister_write(SR_AES_CNTRL_DIR, 0); /* AES_DIR=0 -> encryption */
/* write string to encrypt into buffer */
for(i = 0; i < 16; i++) {
AES_STATE = plain[i] ^ IEEE_VECT;
}
res = crypt();
if(!res)
goto out;
len -= 16;
/* Swiitch Mode */
hal_subregister_write(SR_AES_CNTRL_MODE, 1); /* AES_MODE=1 -> CBC */
hal_subregister_write(SR_AES_CNTRL_DIR, 0); /* AES_DIR=0 -> encryption */
while(len > 0) {
rf230_aes_write_state(plain);
res = crypt();
if(!res)
goto out;
len -= 16;
}
/* Read and retrun cipher */
rf230_aes_read_state(mic);
out:
SREG = sreg;
return res;
}
/* Electonic Code Block */
int
rf230_aes_encrypt_ebc(unsigned char *key, unsigned char *plain, unsigned char *cipher)
{
int res;
uint8_t sreg;
sreg = SREG;
cli();
rf230_aes_write_key(key);
hal_subregister_write(SR_AES_CNTRL_MODE, 0); /* AES_MODE=0 -> ECB for 1:st block*/
hal_subregister_write(SR_AES_CNTRL_DIR, 0); /* AES_DIR=0 -> encryption */
rf230_aes_write_state(plain); /* write string to encrypt into buffer */
res = crypt();
if(!res)
goto out;
rf230_aes_read_state(cipher); /* Read and return cipher */
out:
SREG = sreg;
return res;
}
int
rf230_aes_decrypt_ebc(unsigned char *key, unsigned char *cipher, unsigned char *plain)
{
int res;
uint8_t sreg;
/*
Dummy encryption of 0 w. original key
to get last round key to be used decrytion
*/
sreg = SREG;
cli();
rf230_aes_write_key(key);
hal_subregister_write(SR_AES_CNTRL_MODE, 0); /* AES_MODE=0 -> ECB for 1:st block*/
hal_subregister_write(SR_AES_CNTRL_DIR, 0); /* AES_DIR=0 -> encryption */
memset(tmp, 0, sizeof(tmp)); /* Setup for last round */
rf230_aes_write_state(tmp);
res = crypt();
if(!res)
goto out;
rf230_aes_read_key(tmp);/* Save the last round key */
/* And use as decrytion key */
rf230_aes_write_key(tmp);
hal_subregister_write(SR_AES_CNTRL_MODE, 0); /* AES_MODE=0 -> ECB for 1:st block*/
hal_subregister_write(SR_AES_CNTRL_DIR, 1); /* AES_DIR=1 -> decryption */
/* Write string to decrypt into buffer */
rf230_aes_write_state(cipher);
res = crypt();
if(!res)
goto out;
rf230_aes_read_state(plain); /* Read plaintext into string */
out:
SREG = sreg;
return res;
}
#endif /* AES_128_HW_CONF */