int elgv1vrfy(const mpbarrett* p, const mpbarrett* n, const mpnumber* g, const mpnumber* hm, const mpnumber* y, const mpnumber* r, const mpnumber* s)
{
register size_t size = p->size;
register mpw* temp;
if (mpz(r->size, r->data))
return 0;
if (mpgex(r->size, r->data, size, p->modl))
return 0;
if (mpz(s->size, s->data))
return 0;
if (mpgex(s->size, s->data, n->size, n->modl))
return 0;
temp = (mpw*) malloc((6*size+2)*sizeof(mpw));
if (temp)
{
register int rc;
/* compute u1 = y^r mod p */
mpbpowmod_w(p, y->size, y->data, r->size, r->data, temp, temp+2*size);
/* compute u2 = r^s mod p */
mpbpowmod_w(p, r->size, r->data, s->size, s->data, temp+size, temp+2*size);
/* compute v1 = u1*u2 mod p */
mpbmulmod_w(p, size, temp, size, temp+size, temp+size, temp+2*size);
/* compute v2 = g^h(m) mod p */
mpbpowmod_w(p, g->size, g->data, hm->size, hm->data, temp, temp+2*size);
rc = mpeq(size, temp, temp+size);
free(temp);
return rc;
}
return 0;
}
/*
* needs workspace of (5*size+2) words
*/
int mppmilraba_w(const mpbarrett* p, const mpw* adata, int s, const mpw* rdata, const mpw* ndata, mpw* wksp)
{
register size_t size = p->size;
register int j = 0;
mpbpowmod_w(p, size, adata, size, rdata, wksp, wksp+size);
while (1)
{
if (mpisone(size, wksp))
return (j == 0);
if (mpeq(size, wksp, ndata))
return 1;
if (++j < s)
mpbsqrmod_w(p, size, wksp, wksp, wksp+size);
else
return 0;
}
}