nqrand(3)

NAME

nqrand — random bytes from the operating system

LIBRARY

libnoqtis, -lnoqtis

SYNOPSIS

#include <noqtis.h>

int
nqrand(uint8_t *buf, size_t len);

DESCRIPTION

nqrand() fills buf with len bytes from the operating system's cryptographically secure random source: getrandom(2) on Linux, arc4random_buf(3) on macOS and the BSDs, BCryptGenRandom() on Windows, and getentropy(3) under WebAssembly (WebCrypto getRandomValues() with emscripten, WASI random_get() with wasi-sdk). Large requests are made in chunks. There is no fallback source and no user-space generator: when the operating system's source fails, so does nqrand().

Every function of noqtis(3) that needs randomness (key generation, hedged signing, encapsulation, mask shares) takes it from here.

RETURN VALUES

NQOK: buf holds len random bytes. A len of 0 succeeds and writes nothing.
[NQEARG]: buf is NULL and len is not 0.
[NQERNG]: The operating system's source failed.

EXAMPLES

uint8_t key[32];
if (nqrand(key, sizeof key) != NQOK)
  abort();
/* ... use the key ... */
nqwipe(key, sizeof key);