PATFC: Novel pseudorandom affine transformation-based feistel-network cipher

In this paper, we present a navel symmetric-key block cipher, with variable block and key lengths, referred to as PATFC (Pseudorandom Affine Transformation-based Feistel Cipher), suitable for software and hardware implementations. PATFC adopts the 3-round Luby-Rackoff construction (a compact form of the Feistel network structure) for fusing pseudorandom functions of the plaintext partitions to obtain a pseudorandom permutation. PATFC mainly makes use of a novel keyed pseudorandom function (PRF) that is based on a pseudorandom affine transformation (constructed using a highly nonlinear pseudorandom sequence generator) followed by a data and key dependent encoding and simple hash processes. Extensive statistical tests of PATFC and its underlying PRF consistently demonstrated their competitive diffusion, confusion and pseudorandomness characteristics. Furthermore, PATFC is provably secure and not vulnerable to known/chosen/adaptive plaintext/ciphertext attacks.