Abstract:

Most of the encryption engines in smart cards are designed with high operation concurrency. It takes one clock cycle to execute many encrypt operations, such as S box operations. This  deeply decreased the effect of DPA（Differential  Power  Analysis）. To remove this affect,  the plain-text chosen attack with the DPA was combined. The improved DPA  will only change the inputs of one of the DES（Data Encryption Standard） S box. Using this improved DPA,  the correct key on one of the smart cards with DES encryption has been found. The result shows that the improved DPA on DES encryption can increase the correlation value by 150％ than the traditional DPA analysis.