1 0fc65b37 2004-03-21 devnull #include "os.h"
 2 0fc65b37 2004-03-21 devnull #include <mp.h>
 3 0fc65b37 2004-03-21 devnull #include <libsec.h>
 4 0fc65b37 2004-03-21 devnull 
 5 0fc65b37 2004-03-21 devnull EGsig*
 6 0fc65b37 2004-03-21 devnull egsign(EGpriv *priv, mpint *m)
 7 0fc65b37 2004-03-21 devnull {
 8 0fc65b37 2004-03-21 devnull 	EGpub *pub = &priv->pub;
 9 0fc65b37 2004-03-21 devnull 	EGsig *sig;
10 0fc65b37 2004-03-21 devnull 	mpint *pm1, *k, *kinv, *r, *s;
11 0fc65b37 2004-03-21 devnull 	mpint *p = pub->p, *alpha = pub->alpha;
12 0fc65b37 2004-03-21 devnull 	int plen = mpsignif(p);
13 0fc65b37 2004-03-21 devnull 
14 0fc65b37 2004-03-21 devnull 	pm1 = mpnew(0);
15 0fc65b37 2004-03-21 devnull 	kinv = mpnew(0);
16 0fc65b37 2004-03-21 devnull 	r = mpnew(0);
17 0fc65b37 2004-03-21 devnull 	s = mpnew(0);
18 0fc65b37 2004-03-21 devnull 	k = mpnew(0);
19 0fc65b37 2004-03-21 devnull 	mpsub(p, mpone, pm1);
20 0fc65b37 2004-03-21 devnull 	while(1){
21 0fc65b37 2004-03-21 devnull 		mprand(plen, genrandom, k);
22 0fc65b37 2004-03-21 devnull 		if((mpcmp(mpone, k) > 0) || (mpcmp(k, pm1) >= 0))
23 0fc65b37 2004-03-21 devnull 			continue;
24 0fc65b37 2004-03-21 devnull 		mpextendedgcd(k, pm1, r, kinv, s);
25 0fc65b37 2004-03-21 devnull 		if(mpcmp(r, mpone) != 0)
26 0fc65b37 2004-03-21 devnull 			continue;
27 0fc65b37 2004-03-21 devnull 		break;
28 0fc65b37 2004-03-21 devnull 	}
29 0fc65b37 2004-03-21 devnull 	mpmod(kinv, pm1, kinv);  // make kinv positive
30 0fc65b37 2004-03-21 devnull 	mpexp(alpha, k, p, r);
31 0fc65b37 2004-03-21 devnull 	mpmul(priv->secret, r, s);
32 0fc65b37 2004-03-21 devnull 	mpmod(s, pm1, s);
33 0fc65b37 2004-03-21 devnull 	mpsub(m, s, s);
34 0fc65b37 2004-03-21 devnull 	mpmul(kinv, s, s);
35 0fc65b37 2004-03-21 devnull 	mpmod(s, pm1, s);
36 0fc65b37 2004-03-21 devnull 	sig = egsigalloc();
37 0fc65b37 2004-03-21 devnull 	sig->r = r;
38 0fc65b37 2004-03-21 devnull 	sig->s = s;
39 0fc65b37 2004-03-21 devnull 	mpfree(pm1);
40 0fc65b37 2004-03-21 devnull 	mpfree(k);
41 0fc65b37 2004-03-21 devnull 	mpfree(kinv);
42 0fc65b37 2004-03-21 devnull 	return sig;
43 0fc65b37 2004-03-21 devnull }