Specification of Rijndael

Abstract

In this chapter we specify the cipher structure and the building blocks of Rijndael. After explaining the difference between the Rijndael specifications and the AES standard, we specify the external interface to the ciphers. This is followed by the description of the Rijndael structure and the steps of its round transformation. Subsequently, we specify the number of rounds as a function of the block and key length, and describe the key schedule. We conclude this chapter with a treatment of algorithms for implementing decryption with Rijndael. This chapter is not intended as an implementation guideline. For implementation aspects, we refer to Chap. 4.