A Conjunction for Private Stream Searching

Our contribution defines a conjunction operator for private stream searching. Private stream searching is a system of cryptographic methods that preserves the confidentiality of the search criteria and the result. The system uses an encrypted filter to conceal the search terms, processes a search without decrypting these terms, and saves the result to an encrypted buffer. Fundamentally, the system provides a private search capability based on a logical disjunction of search terms. Our conjunction operator broadens the search capability, and achieves this without significantly increasing the complexity of the private search system. The conjunction is processed as a bit wise summation of hashed keyword values to reference an encrypted entry in the filter. The method is best suited for a conjunction of fields from a record, does not impute a calculation of bilinear map, as required in prior research, and offers a practical utility that integrates into private stream searching. We demonstrate the practicality by including the conjunction operator into our domain specific language for private packet filtering.