Abstract: An approach is disclosed that receives a request from a requestor over a computer network, the request including a set of encrypted user data that includes interest vectors pertaining to a set of users. A homomorphic encryption processing of the encrypted user data is performed using a distance function that utilizes an encrypted lookup table. This results in a set of distance results. An encrypted distance array is then generated from the distance results. The encrypted distance array describes similarities between the users in the set of encrypted data. A set of encrypted recommendations are returned to the requestor. The recommendations returned are derived from the encrypted distance array.