An efficient format-preserving encryption mode for practical domains

Format-preserving encryption (FPE), which makes sure that ciphertext has the same format as plaintext, has been widely used in protecting sensitive data in a database. Aiming at efficiently solving the FPE problem on a collection of practical domains, we propose the RREM (random reference-based encryption mode), which constructs bijection between the original domain and integer set through distance computation. If an appropriate distance function is predefined, the proposed mode can solve the FPE problem on linear equidistance domain in a more efficient way than previous methods. Furthermore, we make a classification on various types of domains, show the application of RREM in some practical domains, and specify RREM??s capability of solving the FPE problem on frequently-used fields in database quite efficiently.