mirror of
https://github.com/0intro/conterm
synced 2024-11-25 07:09:34 +03:00
83 lines
1.4 KiB
C
83 lines
1.4 KiB
C
#include "os.h"
|
|
#include <mp.h>
|
|
#include <libsec.h>
|
|
|
|
static void
|
|
genrand(mpint *p, int n)
|
|
{
|
|
mpdigit x;
|
|
|
|
// generate n random bits with high 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;
|
|
}
|
|
|
|
RSApriv*
|
|
rsagen(int nlen, int elen, int rounds)
|
|
{
|
|
mpint *p, *q, *e, *d, *phi, *n, *t1, *t2, *kp, *kq, *c2;
|
|
RSApriv *rsa;
|
|
|
|
p = mpnew(nlen/2);
|
|
q = mpnew(nlen/2);
|
|
n = mpnew(nlen);
|
|
e = mpnew(elen);
|
|
d = mpnew(0);
|
|
phi = mpnew(nlen);
|
|
|
|
// create the prime factors and euclid's function
|
|
genstrongprime(p, nlen/2, rounds);
|
|
genstrongprime(q, nlen - mpsignif(p) + 1, rounds);
|
|
mpmul(p, q, n);
|
|
mpsub(p, mpone, e);
|
|
mpsub(q, mpone, d);
|
|
mpmul(e, d, phi);
|
|
|
|
// find an e relatively prime to phi
|
|
t1 = mpnew(0);
|
|
t2 = mpnew(0);
|
|
genrand(e, elen);
|
|
for(;;){
|
|
mpextendedgcd(e, phi, d, t1, t2);
|
|
if(mpcmp(d, mpone) == 0)
|
|
break;
|
|
mpadd(mpone, e, e);
|
|
}
|
|
mpfree(t1);
|
|
mpfree(t2);
|
|
|
|
// d = e**-1 mod phi
|
|
mpinvert(e, phi, d);
|
|
|
|
// compute chinese remainder coefficient
|
|
c2 = mpnew(0);
|
|
mpinvert(p, q, c2);
|
|
|
|
// for crt a**k mod p == (a**(k mod p-1)) mod p
|
|
kq = mpnew(0);
|
|
kp = mpnew(0);
|
|
mpsub(p, mpone, phi);
|
|
mpmod(d, phi, kp);
|
|
mpsub(q, mpone, phi);
|
|
mpmod(d, phi, kq);
|
|
|
|
rsa = rsaprivalloc();
|
|
rsa->pub.ek = e;
|
|
rsa->pub.n = n;
|
|
rsa->dk = d;
|
|
rsa->kp = kp;
|
|
rsa->kq = kq;
|
|
rsa->p = p;
|
|
rsa->q = q;
|
|
rsa->c2 = c2;
|
|
|
|
mpfree(phi);
|
|
|
|
return rsa;
|
|
}
|