A system is described that receives first user identifiers from a first user space and a first set of hash values generated from a hash function applied to first information that identify users associated with the set of first user identifiers. The system determines a hash value included in both of the first set of hash values and a second set of hash values that are generated from the hash function being applied to second information that identify users associated with second user identifiers from a second user space. The system generates a mapping between the first user identifiers and the second user identifiers that each correspond to the same hash value. The system determines targeted information directed to the first user identifiers and based on the mapping, outputs the targeted information to user devices associated with the second user identifiers.