A system and method for constraint resolution

A method of determining the compatibility of respective information associated with at least two parties is described. The method comprises: a first and second party each expressing their respective information in an agreed format; processing the information according to a two-phase double-encryption process, in which the first party encrypts their information under a personalized first-phase procedure and sends the results to the second party and the second party encrypts their information under a personalized first-phase procedure and sends the results to the first party, the second party encrypting the encrypted information received from the first party under a personalized second-phase procedure to produce a double-encrypted result and the first party encrypting the encrypted information received from the second party under a personalized second-phase procedure to produce a double-encrypted result, the first- and second-phase procedures being chosen such that a given element of information will always yield the same unique double-encrypted result regardless of which party it originates from; and comparing each party's double-encrypted information to determine the compatibility of the information of each party.