xmss-KAT-generator/prg.c
2015-08-11 12:08:27 +02:00

31 строка
894 B
C

#include "chacha.h"
//#include "params.h"
#include "prg.h"
const unsigned char zero_nonce[12] = {0};
/**
* Generates rlen output bytes using ChaCha20 with a zero nonce and counter = 0
*/
void prg(unsigned char *r, unsigned long long rlen, const unsigned char *key, uint key_len)
{
CRYPTO_chacha_20_keystream(r, rlen, key, zero_nonce, 0);
}
/**
* Generates rlen output bytes using ChaCha20.
* Nonce and counter are set depending on the address addr.
*/
void prg_with_counter(unsigned char *r, unsigned long long rlen, const unsigned char *key, uint key_len, const unsigned char addr[16])
{
int i;
unsigned char nonce[12];
for(i = 0; i < 12; i++)
{
nonce[i] = addr[i];
}
uint32_t counter;
counter = (addr[12] << 24)|(addr[13] << 16)|(addr[14] << 8)|addr[15];
// TODO: Check address handling. Endianess?
CRYPTO_chacha_20_keystream(r, rlen, key, nonce, counter);
}