Confidentiality via camouflage: The CVC approach to disclosure limitation when answering queries to databases

A practical method is presented for giving unlimited, deterministically correct, numerical responses to ad-hoe queries to an online database, while not compromising confidential numerical data. The method is appropriate for any size database, and no assumptions are needed about the statistical distribution of the confidential data. Responses are in the form of a number plus a guarantee, so the user can determine an interval that is sure to contain the exact answer. Virtually any imaginable query type can be answered, and in the absence of insider information, collusion among the users presents no problem. Experimental analysis supports the practical viability of the proposed method.