SOMA: Security Evaluation of Obfuscation Methods via Attack Sequencing

摘要

Hardware intellectual properties (IPs) used in diverse electronic systems face several critical security issues during their life cycle, including piracy, reverse engineering, and extraction of design secrets. To combat these issues, pre-silicon hardware obfuscation or logic locking has emerged as a promising solution and has been an active research topic over the past decade. However, in parallel, a number of functional and structural attacks on obfuscation have been discovered by the research community to break the protection provided by the existing obfuscation schemes. These attacks have played a major role in enhancing the security of hardware obfuscation schemes. In this paper, we introduce a novel combined attack modality, referred to as SOMA, which relies on judiciously combining the existing attacks to produce a significantly more powerful one. We demonstrate that such an attack can expose hidden exploits and measure the level of security offered by a given obfuscation technique. SOMA creates a sequence of attacks, where the outcome of each attack is used to guide the next and concludes with a key-refinement measure to restore the functionality of a locked IP. We demonstrate that SOMA can easily break major existing locking schemes that are believed to be secure with an attack accuracy average of 94.88%.