func lattigo_genBootstrappingKey()

in src/gowrapper/ckks/keygen.go [150:209]
39 lines of code
6 McCabe index (conditional complexity)

func lattigo_genBootstrappingKey(keygenHandle Handle5, paramHandle Handle5, btpParamsHandle Handle5, skHandle Handle5, relinKeyHandle Handle5, rotKeyHandle Handle5) Handle5 {
	var keygen *rlwe.KeyGenerator
	keygen = getStoredKeyGenerator(keygenHandle)

	var params *ckks.Parameters
	params = getStoredParameters(paramHandle)

	var btpParams *ckks.BootstrappingParameters
	btpParams = getStoredBootstrappingParameters(btpParamsHandle)

	var sk *rlwe.SecretKey
	sk = getStoredSecretKey(skHandle)

	// get existing keys
	var relinKey *rlwe.RelinearizationKey
	relinKey = getStoredRelinKey(relinKeyHandle)

	var rotKeys *rlwe.RotationKeySet
	rotKeys = getStoredRotationKeys(rotKeyHandle)

	// generate the set of keys needed for bootstrapping
	btpRots := btpParams.RotationsForBootstrapping(params.LogSlots())

	// galois elements corresponding to the bootstrapping rotation indices
	var galEls []uint64
	for _, k := range btpRots {
		// generate the Galois index for this rotation
		var galoisIdx uint64
		galoisIdx = params.GaloisElementForColumnRotationBy(k)

		// test if this galoisIdx is already in the set of rotation keys.
		// if NOT, add it to galEls so that it will be generated
		if _, ok := rotKeys.Keys[galoisIdx]; !ok {
			galEls = append(galEls, galoisIdx)
		}
	}
	// include a conjugation key
	var conjIdx uint64
	conjIdx = params.GaloisElementForRowRotation()
	if _, ok := rotKeys.Keys[conjIdx]; !ok {
		galEls = append(galEls, conjIdx)
	}

	// galEls contains the Galois indices needed for bootstrapping, but which are not already in the set of rotation keys.
	// Generate a new set of rotation keys for the missing indices, then merge the two maps.
	var btpRotKeys *rlwe.RotationKeySet
	btpRotKeys = (*keygen).GenRotationKeys(galEls, sk)

	for k, v := range btpRotKeys.Keys {
		if _, ok := rotKeys.Keys[k]; ok {
			panic(errors.New("Internal error: Generated a bootstrapping key that is already in the map"))
		}
		rotKeys.Keys[k] = v
	}

	var btpKey ckks.BootstrappingKey
	btpKey = ckks.BootstrappingKey{Rlk: relinKey, Rtks: rotKeys}

	return marshal.CrossLangObjMap.Add(unsafe.Pointer(&btpKey))
}