Exploring the Application of Homomorphic Encryption to a Cross Domain Solution

A Cross Domain Solution (CDS) is a means of secure information exchange that provides the ability to access or transfer digital data between varying security domains. Most existing CDS methods focus on risk management policies that rely on using protected or trusted parties to process the information in order to solve this problem. A CDS that is able to function in the presence of untrusted parties is a challenge. We apply the concepts of homomorphic encryption (HE) to explore a new solution to the CDS problem. We built a practical software case study application using the Yet Another Somewhat Homomorphic Encryption Scheme (YASHE) around the specific challenge of evaluating the gateway bypass condition on encrypted data. We assess the feasibility of such an application through performance and memory profiling in order to find a parameter selection that ensures proper homomorphic evaluation. The correctness of the application was assured for 64-, 72-, 96-, and 128-bit security parameter selections of YASHE resulting in high latency performance. The computing time required by our proof-of-concept implementation may be high but this approach allows the manual process employed in current systems to be eliminated.