Described herein are technologies pertaining to protecting user privacy in connection with attribute-based matching services. A user registers with a platform that includes a plurality of non-collaborating partitions, where registration includes transmitting a message to the platform that indicates that the user has one or more attributes corresponding thereto. Through selective encryption and a communications protocol amongst the partitions, none of the partitions are able to ascertain that the user has the attributes. Acting in conjunction, however, the plurality of partitions perform rich attribute.