Efficient Tweakable Enciphering Schemes From (Block-Wise) Universal Hash Functions

This paper describes several constructions of tweakable strong pseudorandom permutations (SPRPs) built from different modes of operations of a block cipher and suitable universal hash functions. For the electronic codebook (ECB) mode based construction, an invertible blockwise universal hash function is required. We simplify an earlier construction of such a function described by Naor and Reingold. The other modes of operations considered are the output feedback (OFB) mode and a counter-like mode. All the constructions make the same number of block cipher calls and the same number of multiplications. Combined with a class of polynomials defined by Bernstein, the new constructions provide the currently best known algorithms for the important practical problem of disk encryption.