ref: dff1e3813fb0deb18ca790b7c28f6a1405720ff6
dir: /sys/src/libsec/port/genprime.c/
#include "os.h" #include <mp.h> #include <libsec.h> // generate a probable prime. accuracy is the miller-rabin interations void genprime(mpint *p, int n, int accuracy) { mpdigit x; // generate n random bits with high and low bits set mpbits(p, n); genrandom((uchar*)p->p, (n+7)/8); p->top = (n+Dbits-1)/Dbits; x = 1; x <<= ((n-1)%Dbits); p->p[p->top-1] &= (x-1); p->p[p->top-1] |= x; p->p[0] |= 1; mpnorm(p); // keep icrementing till it looks prime for(;;){ if(probably_prime(p, accuracy)) break; mpadd(p, mptwo, p); } }