void multiplication(char* num1, char* num2)
{
int pos1 = 0, pos2 = 0;
del_point(num1, num2, &pos1, &pos2);
int len1 = strlen(num1);
int len2 = strlen(num2);
int result[400] = {0};
int i = len1 - 1, j = len2 - 1;
for (; i >= 0; --i)
{
for (j = len2 - 1; j >= 0; --j)
{
result[i+j+1] += (num1[i] - 48) * (num2[j] - 48);
}
}
int len = strlen(num1) + strlen(num2);
int ilen = len - pos1 - pos2;
for (i = len - 1; i > 0; --i)
{
result[i-1] += result[i] / 10;
result[i] = result[i] % 10;
}
int k = 0;
if (result[0] != 0)
{
num2[k++] = (char)(result[0] + '0');
}
for (i = 1; i < ilen; ++i)
{
num2[k++] = (char)(result[i] + '0');
}
if (pos1 != 0 || pos2 != 0)
{
num2[k++] = '.';
for (i = ilen; i < len; ++i)
{
num2[k++] = (char)(result[i] + '0');
}
}
num2[k] = '\0';
}
/*
* delete the selected row
*/
void del_point_cb(Widget w, XtPointer client_data, XtPointer call_data)
{
EditPoints *ep = (EditPoints *)client_data;
int i,j;
XbaeMatrixGetCurrentCell( ep->mw, &i, &j );
if( i>=ep->nrows || j>=ep->ncols ){
errwin( "Selected cell out of range" );
return;
}
del_point( ep->gno, ep->setno, i+1 );
update_set_status( ep->gno, ep->setno );
if( isactive_set( ep->gno, ep->setno ) ){
update_cells( NULL, (XtPointer)ep, 0 );
}
}
/**
Verify an ECC signature
@param sig The signature to verify
@param siglen The length of the signature (octets)
@param hash The hash (message digest) that was signed
@param hashlen The length of the hash (octets)
@param stat Result of signature, 1==valid, 0==invalid
@param key The corresponding public ECC key
@return CRYPT_OK if successful (even if the signature is not valid)
*/
int ecc_verify_hash(const unsigned char *sig, unsigned long siglen,
const unsigned char *hash, unsigned long hashlen,
int *stat, ecc_key *key)
{
ecc_point *mG, *mQ;
mp_int r, s, v, w, u1, u2, e, p, m;
mp_digit mp;
int err;
LTC_ARGCHK(sig != NULL);
LTC_ARGCHK(hash != NULL);
LTC_ARGCHK(stat != NULL);
LTC_ARGCHK(key != NULL);
/* default to invalid signature */
*stat = 0;
/* is the IDX valid ? */
if (is_valid_idx(key->idx) != 1) {
return CRYPT_PK_INVALID_TYPE;
}
/* allocate ints */
if ((err = mp_init_multi(&r, &s, &v, &w, &u1, &u2, &p, &e, &m, NULL)) != MP_OKAY) {
return CRYPT_MEM;
}
/* allocate points */
mG = new_point();
mQ = new_point();
if (mQ == NULL || mG == NULL) {
err = CRYPT_MEM;
goto done;
}
/* parse header */
if ((err = der_decode_sequence_multi(sig, siglen,
LTC_ASN1_INTEGER, 1UL, &r,
LTC_ASN1_INTEGER, 1UL, &s,
LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
goto done;
}
/* get the order */
if ((err = mp_read_radix(&p, (char *)sets[key->idx].order, 64)) != MP_OKAY) { goto error; }
/* get the modulus */
if ((err = mp_read_radix(&m, (char *)sets[key->idx].prime, 64)) != MP_OKAY) { goto error; }
/* check for zero */
if (mp_iszero(&r) || mp_iszero(&s) || mp_cmp(&r, &p) != MP_LT || mp_cmp(&s, &p) != MP_LT) {
err = CRYPT_INVALID_PACKET;
goto done;
}
/* read hash */
if ((err = mp_read_unsigned_bin(&e, (unsigned char *)hash, (int)hashlen)) != MP_OKAY) { goto error; }
/* w = s^-1 mod n */
if ((err = mp_invmod(&s, &p, &w)) != MP_OKAY) { goto error; }
/* u1 = ew */
if ((err = mp_mulmod(&e, &w, &p, &u1)) != MP_OKAY) { goto error; }
/* u2 = rw */
if ((err = mp_mulmod(&r, &w, &p, &u2)) != MP_OKAY) { goto error; }
/* find mG = u1*G */
if ((err = mp_read_radix(&mG->x, (char *)sets[key->idx].Gx, 64)) != MP_OKAY) { goto error; }
if ((err = mp_read_radix(&mG->y, (char *)sets[key->idx].Gy, 64)) != MP_OKAY) { goto error; }
mp_set(&mG->z, 1);
if ((err = ecc_mulmod(&u1, mG, mG, &m, 0)) != CRYPT_OK) { goto done; }
/* find mQ = u2*Q */
if ((err = mp_copy(&key->pubkey.x, &mQ->x)) != MP_OKAY) { goto error; }
if ((err = mp_copy(&key->pubkey.y, &mQ->y)) != MP_OKAY) { goto error; }
if ((err = mp_copy(&key->pubkey.z, &mQ->z)) != MP_OKAY) { goto error; }
if ((err = ecc_mulmod(&u2, mQ, mQ, &m, 0)) != CRYPT_OK) { goto done; }
/* find the montgomery mp */
if ((err = mp_montgomery_setup(&m, &mp)) != MP_OKAY) { goto error; }
/* add them */
if ((err = add_point(mQ, mG, mG, &m, mp)) != CRYPT_OK) { goto done; }
/* reduce */
if ((err = ecc_map(mG, &m, mp)) != CRYPT_OK) { goto done; }
/* v = X_x1 mod n */
if ((err = mp_mod(&mG->x, &p, &v)) != CRYPT_OK) { goto done; }
/* does v == r */
if (mp_cmp(&v, &r) == MP_EQ) {
*stat = 1;
}
/* clear up and return */
err = CRYPT_OK;
goto done;
error:
err = mpi_to_ltc_error(err);
done:
del_point(mG);
del_point(mQ);
mp_clear_multi(&r, &s, &v, &w, &u1, &u2, &p, &e, &m, NULL);
return err;
}