In location-based services (LBS). as the untrusted LBS server can be seen as an adversary. and it can utilize the attribute as background knowledge to correlate the real location of the user in the set of uncertain locations. Then the adversary can gain the location privacy when the user enjoys the snapshot and continuous query through the correlation inference attack. https://www.tftoyes.shop/product-category/rudolph-the-red-nosed-reindeer/