Interlocking obfuscation for anti-tamper hardware
Interlocking obfuscation for anti-tamper hardware
复制标题
防篡改硬件的联锁混淆
DOI：
10.1145/2459976.2459985
复制
发表时间：
2013
期刊：
影响因子：
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通讯作者：
Simin Hall
中科院分区：
文献类型：
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作者：
Avinash R. Desai;M. Hsiao;Chao Wang;L. Nazhandali;Simin Hall
对芯片进行篡改和逆向工程以提取硬件知识产权 (IP) 核心或注入恶意更改是一个主要问题。容易被篡改的数字系统引起了国防组织的极大关注。首先，离岸芯片制造使得IP核的设计秘密对于代工厂和生产链上的其他实体来说是透明的。其次，如果没有防篡改机制，在制造后可能无法检测到对设计的微小恶意修改。过去已经开发了一些技术来提高对此类攻击的防御能力，但它们往往会成为攻击者不断增强的力量的牺牲品。我们提出了一种通过巧妙的设计混淆来防止篡改的新方法，可以通过特定的动态路径遍历来解锁。因此，控制器的功能模式借助混淆状态被隐藏，并且功能模式仅在状态转换期间形成特定互锁码字时才可操作。不需要比较器，因为混淆嵌入在状态机本身的转换函数中。一个附带的好处是，任何小的改变都会通过混淆的设计被放大。换句话说，设计的改变将表现为电路功能的巨大差异。开源 IP 核套件中的高级加密标准 (AES) 电路的实验结果表明，所提出的方法提供了更好的主动防御机制，以抵御标称 (7.8%) 面积开销的攻击。
Tampering and Reverse Engineering of a chip to extract the hardware Intellectual Property (IP) core or to inject malicious alterations is a major concern. Digital systems susceptible to tampering are of immense concern to defense organizations. First, offshore chip manufacturing allows the design secrets of the IP cores to be transparent to the foundry and other entities along the production chain. Second, small malicious modifications to the design may not be detectable after fabrication without anti-tamper mechanisms. Some techniques have been developed in the past to improve the defense against such attacks but they tend to fall prey to the increasing power of the attacker. We present a new way to protect against tampering by a clever obfuscation of the design, which can be unlocked with a specific, dynamic path traversal. Hence, the functional mode of the controller is hidden with the help of obfuscated states, and the functional mode is made operational only on the formation of a specific interlocked Code-Word during state transition. No comparator is needed as the obfuscation is embedded within the transition function of the state machine itself. A side benefit is that any small alteration will be magnified via the obfuscated design. In other words, an alteration to the design will manifest itself as a large difference in the circuit's functionality. Experimental results on an Advanced Encryption Standard (AES) circuit from the open-source IP-cores suite suggest that the proposed method provides better active defense mechanisms against attacks with nominal (7.8%) area overhead.