防安全芯片中私钥泄露的硬件木马防御研究

Hardware trojan becomes the fatal threat to current information ecosystem. The risk of implanting hardware trojan in largely manufactured chips is increasing because of the globalization trend of ASIC manufacture. Since it is impossible to achieve 100% detection, this project firstly presents the research topic to prevent private key leakage with the hidden torjan tolerant ability in secure chip. From the point view of basic theory and physical implementation, five key problems are chosen to be studied. According to the private key transmission network, the leakage risk is formally and fully analyzed. Based on WDDL (Wave Dynamic Differential Logic) wave-pipeline technique, high resolution fingerprint with self-reference ability and runtime dynamic authentication of key data path is researched. Using the behavior model of involved block and transmission channel PUF (physically unclonable function), physical signature and authentication of a block is researched. For the private key impact scope locking and scatter preventing, PUF based physical cryptography, key data path fingerprint authentication, and ultra-large data flow generation are proposed to achieve this target. To protect the security enhancement circuit, high redundancy and obfuscation based scheme is proposed to improve the viability. And the logical circuit and secure rules are decoupled at physical implementation stage and coupled at runtime, then the purpose of security enhancement can be hidden to attacker. For some reasonable assumptions, the formally provable goal of private key leakage preventing will be achieved.

硬件木马会对信息生态系统构成致命安全威胁，且芯片被植入木马的风险也逐渐提高。针对木马检测无法保证100%检出率，率先提出能容忍隐藏木马的安全芯片中私钥保护这一重要研究命题，从基础理论与物理实现两个角度重点研究5大关键科学问题：研究基于私钥传输网络的私钥泄露风险分析问题，确定所有可能导致私钥泄露的安全漏洞；以WDDL行波流水为基础，利用其旁路信息的良好可鉴别性，研究无参考芯片情况下关键数据通路的高分辨率指纹产生与运行时自验证问题；研究基于关键部件行为模式与传输通路PUF的物理签名与认证问题；研究私钥作用范围锁定与防扩散问题，形成以PUF物理加解密、数据通路实时指纹校验、制造极限数据流量为核心的解决方案；研究安全加固电路自保护问题，基于强冗余高加扰方式提高其生存能力，采用逻辑电路与安全规则物理实现时分离运行时耦合的原则隐藏设计意图。在一定合理化假设前提下，实现可形式化证明的防私钥泄漏安全目标。

硬件木马会对信息生态系统构成致命安全威胁，且芯片被植入木马的风险也逐渐提高。针对木马检测无法保证 100%检出率，本课题提出能容忍隐藏木马的安全芯片中私钥保护这一重要研究命题，首先分析基于私钥传输网络的私钥泄露风险，即找出安全芯片中哪些部分可能导致私钥泄漏，然后采取基于反熔丝一次性可编程查找表标准单元为核心技术措施来防止私钥泄漏。反熔丝电路在编程之后不具有可逆性，且只能编程一次，即使运用反向工程也无法破解反熔丝电路在编程之后的状态，因此基于反熔丝一次可编程查找表的标准单元电路及基于此标准单元构建的ASIC芯片具有非常高的安全特性。芯片设计者可以在硅后进行编程以实现特定的安全控制逻辑，或者注入不可破解的加密密钥实现敏感数据的安全存储。在芯片制造出来之前，除芯片设计者之外其他个人或实体不掌握芯片的完整功能，因此很难在芯片制造过程中注入针对性的木马后门电路使芯片的安全控制逻辑失效，或者泄漏芯片内部状态信息。以反熔丝一次性可编程查找表标准单元为基础，本课题研究了ASIC芯片设计实现方法，安全芯片内部数据和密钥的加密存储与解密方法，以及安全芯片合法性鉴别方法，从多个实现安全芯片内私钥防泄漏这一技术目标。