A New Approach in Key Generation and Expansion in Rijndael Algorithm

Naim Ajlouni¹, Asim El-Sheikh², and Abdullah Abdali Rashed²

¹Amman Arab University for Graduate Studies, Jordan

²Arab Academy for Banking and Financial Science, Jordan

 Abstract: This paper presents a new algorithm that simplifies the process of generating and expanding cipher key, which is considered one of the most important elements in ciphering process. The algorithm generates a random pool of keys (long size key), this key is sent to the authorized receiver. During the ciphering process the algorithm will select the schedule keys randomly from the pool of keys. The receiver will be given the index of the first element in the schedule key and the key length. During the deciphering process the deciphering algorithm will use the received information to extract the schedule from the original pool, this key is then used to decipher the ciphered data block without any key re-expansion.

 Keywords: Rijndael block cipher, AES, key generation, key expansion.