Abstract:
Encryption plays a very significant role in keeping a computer system secure in our
digital world. The most common encryption algorithms include Data Encryption
Standard (DES) and Advanced Encryption Standard (AES). But DES uses a small key
size of 64 bits which makes it vulnerable for attacks.
AES is the new encryption standard and employs a 2-dimensional structure of data
during the encryption. In addition, AES permits a range of key sizes from 128 to 256
bits. These two essences make AES a strong encryption method. Even though
presently there is no report of AES being attacked, there are some efforts going on and
no one can guarantee that AES will survive.
In addition, the rapid acceleration of high computing power could make AES exposed
in the near future. In this thesis, we propose a new encryption algorithm based on the
underlying mechanism of AES. Our work, called Cube-AES in short, extends the AES
encryption algorithm in two ways. One is to use a 3-dimensional structure of data, and
the other is to increase the key size to 512 bits.
We implemented the new algorithm and compared the performance of this algorithm
with that of AES. We found that our method is about 2.28 times slower than that of
AES. The reason is that there are about three times as many operations in Cube-AES
compared with those in AES. We also measured the degree of diffusion and found
that, in most cases, the algorithm gave a higher degree of diffusion than that of AES.