Equivalence between MAC, WCR and PRF for Blockcipher Based Constructions
In FSE’10, Nandi proved a sufficient condition of pseudo random function (PRF) for affine domain extensions (ADE), a wide class of blockcipher based domain extensions. This sufficient condition is satisfied by all known ADE, however, it is not a characterization of PRF. In this paper we completely characterize the ADE and show that weaker security notions message authentication code (MAC) and weakly collision resistant (WCR) are indeed equivalent to PRF.