webadmin/pico-rng
1
0
Fork 0
mirror of https://github.com/polhenarejos/pico-rng.git synced 2026-04-09 17:25:51 +02:00
Code Issues Packages Projects Releases Wiki Activity

Adding the same RNG provided in pico-hsm (https://github.com/polhenarejos/pico-hsm).

Browse Source 
Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>
This commit is contained in:
Pol Henarejos
2022-08-19 14:42:28 +02:00
parent c81b642ec1
commit 4a54c5267d
1 changed files with 32 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
firmware/pico_rng.c
View File

@@ -11,6 +11,7 @@
#include "pico/stdlib.h"
#include "hardware/gpio.h"
#include "hardware/adc.h"
#include "hardware/structs/rosc.h"
// For memcpy
#include <string.h>
@@ -26,6 +27,12 @@
// For resetting the USB controller
#include "hardware/resets.h"
#include "pico/time.h"
static inline uint32_t board_millis(void)
{
return to_ms_since_boot(get_absolute_time());
}
// Device descriptors
#include "pico_rng.h"
@@ -552,26 +559,31 @@ void ep0_out_handler(uint8_t *buf, uint16_t len) {
* @param len the length of the random data in bytes
*/
void get_random_data(char *buf, uint16_t len) {
uint16_t adc_result;
uint8_t size;
int i;
gpio_put(25, 1);
if(len > 64)
{
//TODO handle length error
size = 64;
}
uint64_t word = 0x0;
if (len > 64)
len = 64;
memset(buf, 0, len);
for(i = 1; i <= len; i=i+1)
{
adc_result = adc_read();
memcpy(&buf[i-1], (void*)&adc_result, 2);
/* This algorithm generates 2 words, i.e., 8 bytes. */
for (int i = 0; i < len; i += 8) {
uint64_t random_word = 0xcbf29ce484222325;
for (int round = 0; round < 8; round++)
{
for (int n = 0; n < 64; n++)
{
uint8_t bit1, bit2;
do
{
bit1 = rosc_hw->randombit & 0xff;
// sleep_ms(1);
bit2 = rosc_hw->randombit & 0xff;
} while (bit1 == bit2);
word = (word << 1) | bit1;
}
random_word ^= word^board_millis()^adc_read();
random_word *= 0x00000100000001B3;
}
memcpy(buf + i, &random_word, sizeof(random_word));
}
gpio_put(25, 0);
}
/**
@@ -597,14 +609,10 @@ int main(void) {
// Enable uart debug messages
stdio_init_all();
// Builtin GPIO
gpio_init(25);
gpio_set_dir(25, GPIO_OUT);
// ADC
adc_init();
adc_gpio_init(26);
adc_select_input(0);
adc_gpio_init(27);
adc_select_input(1);
printf("USB pico rng\n");
usb_device_init();