E2 - A new 128-bit block cipher

This paper describes the design principles, the specification, and evaluati ons of a new 128-bit block cipher E2**, which was proposed to the AES (Adva nced Encryption Standard) candidates. This algorithm supports 128-bit, 192- bit, and 256-bit secret keys. The design philosophy of E2 is highly conserv ative; the structure uses 12-round Feistel as its main function whose round function is constructed with 2-round SPN structure. and initial/final tran sformational functions. E2 has practical security against differential atta ck, linear attack, cryptanalysis with impossible differential, truncated di fferential attack, and so on. Furthermore, E2 can be implemented efficientl y and flexibly on various platforms because the primitive operations involv e byte length processing.