基于状态映射的AES算法硬件混淆设计

Design of Hardware Obfuscation AES Based on State Deflection Strategy

代码混淆利用系统自身逻辑来保护内部重要信息和关键算法,常用于软件代码的安全防护,确保开发者和用户的利益。如何在硬件电路上实现混淆、保护硬件IP核的知识产权,也是亟待解决的问题。该文通过对硬件混淆和AES算法的研究,提出一种基于状态映射的AES算法硬件混淆方案。该方案首先利用冗余和黑洞两种状态相结合的状态映射方式,实现有限状态机的混淆;然后,采用比特翻转的方法,实现组合逻辑电路的混淆;最后,在SMIC 65 nm CMOS工艺下设计基于状态映射的AES算法硬件混淆电路,并采用Toggle、数据相关性和代码覆盖率等评价硬件混淆的效率和有效性。实验结果表明,基于状态映射的AES算法硬件混淆电路面积和功耗分别增加9%和16%,代码覆盖率达到93%以上。

Obfuscation is used to safeguard lawful rights and interests of developers and users in software security, by protecting critical information and algorithms with the system logic relation. Also, how to achieve obfuscation method to protect the hardware IP core is becoming an urgent problem. In this paper, a hardware obfuscation scheme based on deflection strategy is proposed by studying the obfuscation method and the AES algorithm. The deflection strategy with redundancy and black hole states are used to realize the Finite State Machine（FSM） obfuscation, and the bit flip method is used to realize the combinational logic obfuscation. Finally, the proposed hardware obfuscation AES algorithm is designed in SMIC 65 nm CMOS process. The parameters of toggle, data correlation and code coverage are selected to evaluate the efficiency and effectiveness of hardware confusion. Experimental results show that the area and power consumption of the hardware obfuscation AES algorithm is increased by 9% and 16% respectively, and the code coverage rate is over 93%.