borgware-2d/random/prng.c

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/**
* \author Daniel Otte
* \date 2008-08-24
* \license GPLv3 or later
* \brief random number generator based on noekeon running in CFB-mode
*
*/
#include "noekeon.h"
#include "memxor.h"
#include <stdint.h>
#include <string.h>
uint8_t random_state[16];
uint8_t random_key[16];
uint8_t random8(void){
static uint8_t sr[16];
static uint8_t i=0;
if(i==0){
noekeon_enc(random_state, random_key);
memcpy(sr, random_state, 16);
i=15;
return sr[15];
}
--i;
return sr[i];
}
void random_block(void* dest){
noekeon_enc(random_state, random_key);
memcpy(dest, random_state, 16);
}
void srandom32(uint32_t seed){
memcpy(random_key, &seed, 4);
}
void random_seed(const void* buffer){
memcpy(random_key, buffer, 16);
}
void random_add(const void* buffer){
memxor(random_key, buffer, 16);
}