int elgv1sign(const mpbarrett* p, const mpbarrett* n, const mpnumber* g, randomGeneratorContext* rgc, const mpnumber* hm, const mpnumber* x, mpnumber* r, mpnumber* s)
{
register size_t size = p->size;
register mpw* temp = (mpw*) malloc((8*size+6)*sizeof(mpw));
if (temp)
{
/* get a random k, invertible modulo (p-1) */
mpbrndinv_w(n, rgc, temp, temp+size, temp+2*size);
/* compute r = g^k mod p */
mpnfree(r);
mpnsize(r, size);
mpbpowmod_w(p, g->size, g->data, size, temp, r->data, temp+2*size);
/* compute x*r mod n */
mpbmulmod_w(n, x->size, x->data, r->size, r->data, temp, temp+2*size);
/* compute -(x*r) mod n */
mpneg(size, temp);
mpadd(size, temp, n->modl);
/* compute h(m) - x*r mod n */
mpbaddmod_w(n, hm->size, hm->data, size, temp, temp, temp+2*size);
/* compute s = inv(k)*(h(m) - x*r) mod n */
mpnfree(s);
mpnsize(s, size);
mpbmulmod_w(n, size, temp, size, temp+size, s->data, temp+2*size);
free(temp);
return 0;
}
return -1;
}
int dsasign(const mpbarrett* p, const mpbarrett* q, const mpnumber* g, randomGeneratorContext* rgc, const mpnumber* hm, const mpnumber* x, mpnumber* r, mpnumber* s)
{
register size_t psize = p->size;
register size_t qsize = q->size;
register mpw* ptemp;
register mpw* qtemp;
register mpw* pwksp;
register mpw* qwksp;
register int rc = -1;
ptemp = (mpw*) malloc((5*psize+2)*sizeof(mpw));
if (ptemp == (mpw*) 0)
return rc;
qtemp = (mpw*) malloc((9*qsize+6)*sizeof(mpw));
if (qtemp == (mpw*) 0)
{
free(ptemp);
return rc;
}
pwksp = ptemp+psize;
qwksp = qtemp+3*qsize;
/* allocate r */
mpnfree(r);
mpnsize(r, qsize);
/* get a random k, invertible modulo q; store k @ qtemp, inv(k) @ qtemp+qsize */
mpbrndinv_w(q, rgc, qtemp, qtemp+qsize, qwksp);
/* g^k mod p */
mpbpowmod_w(p, g->size, g->data, qsize, qtemp, ptemp, pwksp);
/* (g^k mod p) mod q - simple modulo */
mpmod(qtemp+2*qsize, psize, ptemp, qsize, q->modl, pwksp);
mpcopy(qsize, r->data, qtemp+psize+qsize);
/* allocate s */
mpnfree(s);
mpnsize(s, qsize);
/* x*r mod q */
mpbmulmod_w(q, x->size, x->data, r->size, r->data, qtemp, qwksp);
/* add h(m) mod q */
mpbaddmod_w(q, qsize, qtemp, hm->size, hm->data, qtemp+2*qsize, qwksp);
/* multiply inv(k) mod q */
mpbmulmod_w(q, qsize, qtemp+qsize, qsize, qtemp+2*qsize, s->data, qwksp);
rc = 0;
free(qtemp);
free(ptemp);
return rc;
}
