/*
* Given private-capable privKey, initialize pubKey to be its corresponding
* public key.
*/
feeReturn feePubKeyInitPubKeyFromPriv(feePubKey privKey,
feePubKey pubKey)
{
pubKeyInst *privInst = (pubKeyInst *)privKey;
pubKeyInst *pubInst = (pubKeyInst *)pubKey;
if((privInst == NULL) || (pubInst == NULL)) {
return FR_BadPubKey;
}
if(privInst->privGiant == NULL) {
return FR_IncompatibleKey;
}
pubInst->cp = curveParamsCopy(privInst->cp);
if(pubInst == NULL) {
return FR_Memory;
}
pubInst->plus = new_public_with_key(privInst->plus, pubInst->cp);
if(pubInst->plus == NULL) {
return FR_Memory;
}
if(pubInst->cp->x1Minus != NULL) {
pubInst->minus = new_public_with_key(privInst->minus, pubInst->cp);
if(pubInst->minus == NULL) {
return FR_Memory;
}
}
return FR_Success;
}
/*
* Alloc and init a feeFEEDExp object associated with specified feePubKey.
*/
feeFEEDExp feeFEEDExpNewWithPubKey(
feePubKey pubKey,
feeRandFcn randFcn, // optional
void *randRef)
{
feedInst *finst = (feedInst *) fmalloc(sizeof(feedInst));
giant privGiant;
finst->cp = curveParamsCopy(feePubKeyCurveParams(pubKey));
finst->plus = new_public_with_key(feePubKeyPlusCurve(pubKey),
finst->cp);
finst->minus = new_public_with_key(feePubKeyMinusCurve(pubKey),
finst->cp);
/*
* These might yield NULL data; we can only encrypt in that case.
*/
privGiant = feePubKeyPrivData(pubKey);
if(privGiant) {
finst->gPriv = newGiant(finst->cp->maxDigits);
gtog(privGiant, finst->gPriv);
}
else {
finst->gPriv = NULL;
}
/*
* Conservative, rounding down, on plaintext blocks since we don't
* want to split bytes.
*/
if(finst->cp->primeType == FPT_General) {
unsigned blen = bitlen(finst->cp->basePrime);
finst->plainBlockSize = blen / 8;
if((blen % 8) == 0) {
/*
* round down some more...
*/
finst->plainBlockSize--;
}
}
else {
finst->plainBlockSize = finst->cp->q / 8;
if(((finst->cp->q & 0x7) == 0) && (finst->cp->k > 0)) {
/*
* Special case, with q mod 8 == 0. Here we have to trim back
* the plainBlockSize by one byte.
*/
finst->plainBlockSize--;
}
}
/*
* One block of ciphertext - two giants (with implied sign) and a
* parity byte
*/
finst->cipherBlockSize = (2 * finst->cp->minBytes) + 1;
finst->xp = newGiant(finst->cp->maxDigits);
finst->xc = newGiant(finst->cp->maxDigits);
finst->xq = newGiant(finst->cp->maxDigits);
finst->xm = newGiant(finst->cp->maxDigits);
finst->xaux = newGiant(finst->cp->maxDigits);
finst->rand = NULL;
finst->randData = NULL;
finst->randFcn = randFcn;
finst->randRef = randRef;
return finst;
}
