diff options
Diffstat (limited to 'src/libsec/port/genprime.c')
-rw-r--r-- | src/libsec/port/genprime.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/src/libsec/port/genprime.c b/src/libsec/port/genprime.c new file mode 100644 index 00000000..c0e16d92 --- /dev/null +++ b/src/libsec/port/genprime.c @@ -0,0 +1,27 @@ +#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; + + // keep icrementing till it looks prime + for(;;){ + if(probably_prime(p, accuracy)) + break; + mpadd(p, mptwo, p); + } +} |