Subversion Repositories planix.SVN

#include "os.h"

#include <mp.h>

#include <libsec.h>

RSApriv*

rsafill(mpint *n, mpint *e, mpint *d, mpint *p, mpint *q)

{

	mpint *c2, *kq, *kp, *x;

	RSApriv *rsa;

	// make sure we're not being hoodwinked

	if(!probably_prime(p, 10) || !probably_prime(q, 10)){

		werrstr("rsafill: p or q not prime");

		return nil;

	}

	x = mpnew(0);

	mpmul(p, q, x);

	if(mpcmp(n, x) != 0){

		werrstr("rsafill: n != p*q");

		mpfree(x);

		return nil;

	}

	c2 = mpnew(0);

	mpsub(p, mpone, c2);

	mpsub(q, mpone, x);

	mpmul(c2, x, x);

	mpmul(e, d, c2);

	mpmod(c2, x, x);

	if(mpcmp(x, mpone) != 0){

		werrstr("rsafill: e*d != 1 mod (p-1)*(q-1)");

		mpfree(x);

		mpfree(c2);

		return nil;

	}

	// compute chinese remainder coefficient

	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, x);

	mpmod(d, x, kp);

	mpsub(q, mpone, x);

	mpmod(d, x, kq);

	rsa = rsaprivalloc();

	rsa->pub.ek = mpcopy(e);

	rsa->pub.n = mpcopy(n);

	rsa->dk = mpcopy(d);

	rsa->kp = kp;

	rsa->kq = kq;

	rsa->p = mpcopy(p);

	rsa->q = mpcopy(q);

	rsa->c2 = c2;

	mpfree(x);

	return rsa;

}