A white-box CLEFIA implementation for mobile devices

A difficult problem in mobile internet security is how to prevent key leakage when using traditional symmetric cryptographic algorithms in mobile devices, because mobile devices face with White-Box attacking environment so the cryptographic program running on mobile devices can be fully controlled by attackers. In the other hand, the memory space in mobile devices is relatively limited compared with most computers, so an anti-key-leakage tiny cryptographic algorithms is needed for mobile devices which have relatively high degree of security and high efficiency meanwhile. This paper puts forward two White-Box CLEFIA implementations according to the special structure of CLEFIA. Compared with Chow's White-Box AES, one of the methods can minimize the size of memory space occupied and improve the calculation efficiency by adding random numbers into each step of CLEFIA. And the other method put forward a new structure of lookup table by increasing its dimension. At last, an efficiency test and some simple security comments are proposed.