ref: a79465e118a0469bbda928f86b9eef6b42d18593
dir: /sys/src/libsec/port/genrandom.c/
#include "os.h" #include <libsec.h> static void init(Chachastate *cs) { ulong seed[11]; int i; for(i=0; i<nelem(seed); i++) seed[i] = truerand(); setupChachastate(cs, (uchar*)&seed[0], 32, (uchar*)&seed[8], 12, 20); memset(seed, 0, sizeof(seed)); } static void fill(Chachastate *cs, uchar *p, int n) { Chachastate c; c = *cs; chacha_encrypt((uchar*)&cs->input[4], 32, &c); if(++cs->input[13] == 0) if(++cs->input[14] == 0) ++cs->input[15]; chacha_encrypt(p, n, &c); memset(&c, 0, sizeof(c)); } void genrandom(uchar *p, int n) { static QLock lk; static Chachastate cs; qlock(&lk); if(cs.rounds == 0) init(&cs); cs.input[4] ^= getpid(); /* fork protection */ fill(&cs, p, n); qunlock(&lk); }