AES Algorithm Implemented for PDA Secure Communication with Java

Since Rijndael algorithm was selected as the AES (advanced encryption system) to substitute the DES (data encryption standard), the foremost concern for people has been its security. The result of new attack methods shows that there may be some lacuna in the design of S-box and key schedule with AES algorithm. The problem is the weakness of linearity existing in the S-box and key schedule. In order to keep from the new attacks and implement the AES for PDA secure communication in Java, we analyze in detail on the AES algorithm and give out a new implementation scheme for increasing complexity of nonlinear transformation in design of S-box. The experimental results show our implementation scheme with Java is feasible for the PDA application and is of an acceptable speed for data encryption and decryption.