White-box cryptography system for confusing wheel boundary and method

Abstract

The invention relates to a white-box cryptography system for executing block cipher algorithms such as an AES (Advanced Encryption Standard), in particular to a method for enhancing the white-box cryptography security. The method comprises the following steps: under the situation of a given key, finishing encryption or decryption by a network of a plurality of lookup tables executing crypto-operation together, wherein the lookup table network can be partitioned into a plurality of lookup table groups which are executed in series and similar in structures, certain lookup table groups are relevant to the key while certain lookup table groups are irrelevant to the key, and the total quantity of the lookup table groups is random; and adding a random quantity of confused lookup table groups to increase the difficulty for an attacker to determine each wheel boundary in white-box implementation. In the presence of the lookup table network, the difficulty for the attacker to determine the wheel boundary of an original block cipher is high, so that a method for making attacks with the input and output of a single wheel becomes difficult.

Description

technical field [0001] The invention belongs to the field of information technology, and relates to a white-box cryptosystem for encrypting or decrypting by using a plurality of look-up table networks jointly performing cryptographic operations under the condition of a given key. The invention also relates to a method of increasing the security of white-box cryptography. Background technique [0002] With the development of information technology, more and more consumer electronics (CE) are designed to directly access the Internet (or access the Internet indirectly through the PC platform as a proxy), so as to obtain digital content distributed through the Internet anytime and anywhere. These CE products include but are not limited to digital set-top boxes, IPTVs, PCs, and increasingly handheld devices such as mobile phones and tablet computers. Software applications installed in these CE products can perform operations such as parsing and playing digital content. Due to t...

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Problems solved by technology

[0007] at 15 th "Cryptanalysis of Generic Class of White-Box Implementations" (hereinafter referred to as "Michiels1") by W.Michiels, P.Gorissen and H.D.L.Hollmann in Annual Workshop on Selected Areas inCryptography (SAC2008, Sackville, New Brunswick, Canada, 2008) points out Chow's white box for creating cryptographic algorithms A weakness of the implemented method is that the linear diffusion operation in each round in the white-box implementation is difficult to hide with nonlinear encoding

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