A Novel Luby-Rackoff Based Cipher in a New Feistel-Network Based LPRKES for Smart Cards

The RKES (Remotely Keyed Encryption Schemes) are greatly useful in solving the vital problem of how to do bulk encryption and decryption for high-bandwidth applications (like multimedia and video encryption) in a way that takes advantage of both the superior power of the host and the superior security of the smart card. In this way, the authors propose a novel length preserving (LP) RKES by using a proposed general view of Feistel-Network (FN) in which they use only two rounds in an efficient way. The proposed LPRKES needs a strong Pseudorandom Permutation (PRP) as its basic building block, so the authors introduce a new symmetric key block cipher, with variable block and key lengths, referred to as NLMSFC (Nonlinear Matrix Structure Based Feistel Cipher).