#include "os.h"#include <mp.h>#include <libsec.h> mpint*dh_new(DHstate *dh, mpint *p, mpint *q, mpint *g){	mpint *pm1;	int n; 	memset(dh, 0, sizeof(*dh));	if(mpcmp(g, mpone) <= 0)		return nil; 	n = mpsignif(p);	pm1 = mpnew(n);	mpsub(p, mpone, pm1);	dh->p = mpcopy(p);	dh->g = mpcopy(g);	dh->q = mpcopy(q != nil ? q : pm1);	dh->x = mpnew(mpsignif(dh->q));	dh->y = mpnew(n);	for(;;){		mpnrand(dh->q, genrandom, dh->x);		mpexp(dh->g, dh->x, dh->p, dh->y);		if(mpcmp(dh->y, mpone) > 0 && mpcmp(dh->y, pm1) < 0)			break;	}	mpfree(pm1); 	return dh->y;} mpint*dh_finish(DHstate *dh, mpint *y){	mpint *k = nil; 	if(y == nil || dh->x == nil || dh->p == nil || dh->q == nil)		goto Out; 	/* y > 1 */	if(mpcmp(y, mpone) <= 0)		goto Out; 	k = mpnew(mpsignif(dh->p)); 	/* y < p-1 */	mpsub(dh->p, mpone, k);	if(mpcmp(y, k) >= 0){Bad:		mpfree(k);		k = nil;		goto Out;	} 	/* y**q % p == 1 if q < p-1 */	if(mpcmp(dh->q, k) < 0){		mpexp(y, dh->q, dh->p, k);		if(mpcmp(k, mpone) != 0)			goto Bad;	} 	mpexp(y, dh->x, dh->p, k); Out:	mpfree(dh->p);	mpfree(dh->q);	mpfree(dh->g);	mpfree(dh->x);	mpfree(dh->y);	memset(dh, 0, sizeof(*dh));	return k;}