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