The qualities of Physical Unclonable Functions (PUFs) suffer from several noticeable degradations due to silicon aging. In this paper, we investigate the long-term effects of silicon aging on PUFs derived from the start-up behavior of Static Random Access Memories (SRAM). Previous research on SRAM aging is based on transistor-level simulation or accelerated aging test at high temperature and voltage to observe aging effects within a short period of time. In contrast, we have run a long-term continuous power-up test on 16 Arduino Leonardo boards under nominal conditions for two years. In total, we collected around 175 million measurements for reliability, uniqueness and randomness evaluations. Analysis shows that the number of bits that flip with respect to the reference increased by 19.3% while min-entropy of SRAM PUF noise improves by 19.3% on average after two years of aging. The impact of aging on reliability is smaller under nominal conditions than was previously assessed by the accelerated aging test. The test we conduct in this work more closely resembles the conditions of a device in the field, and therefore we more accurately evaluate how silicon aging affects SRAM PUFs.
A Proof of Concept SRAM-based Physically Unclonable Function (PUF) Key Generation Mechanism for IoT Devices
本文提供了使用基于SRAM的物理不可克隆功能（PUF）为IoT设备生成私钥的概念证明。利用PUF，因为对存储在IoT设备的存储器中的秘密密钥的保护不足。我们利用定制的Arduino mega shield按需从SRAM芯片中提取指纹。我们利用三进制状态的概念，以排除容易翻转的单元，使我们能够从SRAM的指纹提取稳定的位。使用为我们的SRAM器件定制的软件，我们可以控制PUF的出错率，以实现用于密钥生成的可调的基于存储器的PUF。我们利用几个模糊提取技术的基础上，使用不同的纠错编码方法来产生的秘密密钥从SRAM的PUF，并研究之间的权衡错误认证率和错误拒绝率的PUF。
