WARX:efficient white-box block cipher based on ARX primitives and random MDS matrix

White-box cryptography aims to provide secure cryptographic primitives and implementations for the white-box attack model,which assumes that an adversary has full access to the implementation of the cryptographic algorithms.Real-world applications require highly efficient and secure white-box schemes,whereas the existing proposals cannot meet this demand.In this paper,we design a new white-box block cipher based on addition/rotation/XOR(ARX)primitives and random maximal distance separable(MDS)matrix,white-box ARX(WARX),aiming for efficient implementations in both black-and white-box models.The implementation of WARX in the black-box model is nine times faster than SPNbox-16 from ASI-ACRYPT'16,and the implementation in the white-box model is more efficient than SPNbox-16 and WEM from CT-RSA'17.Moreover,the security of WARX in both black-and white-box models is analyzed,which ensures its practical applicability.The design of WARX shows that ARX primitives and random linear layer can improve the efficiency of a white-box block cipher.This article may inspire more provably secure and efficient white-box block ciphers and help to narrow the gap between provably secure white-box schemes from academia and highly applicable schemes in great demand from industry.