This paper proposes Rijndael encryption and decryption which runs its symmetric cipher algorithm called AES. The four stages of AES are divided to ten pipeline stages with the modification that the Byte Substitute is operated after the Shift Row block. This proposed swapping operation has no effect on the Modified AES encryption algorithm. This swapping modernizes the process in parallel manner. This technique is implemented using composite field arithmetic byte substitution for S box. The high throughput can be achieved by inserting some registers in appropriate points making the delay shortest. The simulation results show that the proposed AES has higher throughput with a saving hardware area.
Keywords: Sub Bytes, Shift Rows. Key expansion, pipeline, GF (24)2.