Date Added: Feb 2012
The Substitution-Permutation Network (SPN) is a fundamental block cipher model which is designed to implement Shannon's suggestions of confusion and diffusion. And the Feistel network is also one of the most famous architecture for the design of block cipher. The Feistel structure was proposed by H. Feistel, and was adopted in DES and some other block-ciphers. Later, Schneier and Kelsey extended the Feistel cipher to Generalized Feistel Ciphers (GFC). Adams applied generalized Feistel structure to the design of CAST-256. In this paper, the authors will discuss about generalized Feistel network employ SPN or PSN as its round function, and they want to provide the practical security results of these two models.