struct cprng {
	uint32_t key[8];
};

#define	CPRNG_SEED_BYTES	32

void
cprng_seed(struct cprng *cprng, const void *seed)
{

	(void)memcpy(cprng->key, seed, CPRNG_SEED_BYTES);
}

void
cprng256(struct cprng *cprng, void *buf)
{
	const uint32_t nonce[4] = {0};
	uint32_t output[16];

	crypto_core(output, nonce, cprng->key, crypto_core_constant32);
	(void)memcpy(cprng->key, output, 8);
	(void)memcpy(buf, output + 8, 8);
}