Fast implementation of AES cryptographic algorithms in smart cards

The National Institute of Standards and Technology (NIST) of US announced Rijndael algorithm as the advanced encryption standard (AES) in October 2000, Despite AES surpassing in security the data encryption standard (DES), it is still rare to be implemented in smart cards, due to the reason of deficient AES coprocessors. Here a chip operation system (COS) called NexCard, which derived from Microsoft´s Windows COS, is used as the AES implementation platform. After a suitable COS architecture design for AES and methodology of efficient memory usage, the simulation result shows that direct embedding AES encryption attains 0.56 ms at system clock 15 MHz on the INFINEON SLE66CX322P chip without existence of coprocessor. Corresponding to the development needs in smart card cryptographic algorithm implementations, and different level of the security design specifications, a concept to conjoin numbers of algorithms into single smart card called cipher system on demand (CSOD) method is accomplished in this study concurrently. This is a method utilizing the multiapplication capability of NexCard v2.0 to execute the same AES algorithm as an on-card applet. Although the performance of CSOD is not as good as AES embedded method, CSOD can provide the same result in the situation of adaptability and extendibility.