Random anchor position privacy protection method and system based on homomorphic encryption

The invention discloses a random anchor position privacy protection method and a system based on homomorphic encryption, and belongs to the technical field of position dependent services. The method comprises the steps that a client selects a familiar anchor, and randomly selects an anchor point as a random anchor based on the familiar anchor; the client sends content query information to an LBS (Location Based Service) server, the content query information at least comprises query content and a public key, so that the LBS server generates an encrypted coordinate set of the target interest point according to the content query information and sends the coordinate set to a safety calculation server; the client performs incremental query on the safety calculation server based on the familiar anchor and the random anchor, so that the safety calculation server obtains encrypted nearest neighbor coordinate information of the client according to the encrypted coordinate set of the target interest point; and the clie