Hybrid WBC: Secure and efficient white-box encryption schemes

Abstract

White-box cryptography aims at providing security against an adversary that has access to the encryption process. Numerous whitebox encryption schemes were proposed since the introduction of whitebox cryptography by Chow et al. in 2002. However, most of them are slow, and thus, can be used in practice only to protect very small amounts of information, such as encryption keys. In this extended abstract we present a new threat model for whitebox cryptography which corresponds to the practical abilities of the adversary in a wide range of applications. Furthermore, we study design criteria for white-box primitives that are important from the industry point of view. Finally, we propose a class of new primitives that combine a white-box algorithm with a standard block cipher to obtain white-box protection for encrypting long messages, with high security and reasonable performance.