Methods for practical whitebox cryptography

Abstract

White box cryptography is the new technique against attacks on white box attack environments. In white box attack model, the attacker is even stronger than in black box attack model, and the attacker can monitor all intermediate values. Therefore, safety algorithms are needed against all operation steps being exposure. Chow introduced secure white box cryptography with AES DES implementations against white box attack model [1,2]. However, slower performance by operating too many look up tables is a problem of practical use of white box cryptography. Also key updating on dynamic situations of white box cryptography is much harder than key updating of black box cryptography. Thus, this paper suggests using a specific mode of operation to improve speed of white box implementations, and show concrete examples of enhancement of performance. Also, it suggests a technique of key updating with dynamic and static tables in practically.