TWC: Small: New Directions in Field Programmable Gate Arrays (FPGA) Security

现场可编程门阵列（FPGA）代表了一个重要的计算基础设施，必须保护免受攻击。它们用于各种各样的应用，包括网络路由器、卫星、军事设备和汽车等。 将FPGA编程信息存储在设备外部的存储器中会产生一个天然的安全弱点，迄今为止，主要通过比特流加密来解决。最近的工作表明，比特流加密并非不受攻击，并且通过足够的努力，可以从比特流确定部分或全部FPGA设计的逻辑功能。这项工作系统地研究了先进的攻击FPGA设计，更重要的是，制定健全的对策，对FPGA设计操纵确定的攻击者。为了消除弱点，FPGA安全性从一个新的角度来解决：使用硬件混淆，使FPGA设计的真实功能几乎无法破译，即使整个逻辑级设计可以通过比特流逆向工程来确定。这些问题的解决，首先开发了一系列基于搜索的计算机辅助设计工具，可以识别安全原语（如加密原语）在FPGA设计逻辑级网表。作为这项工作的结果，一系列的自动化工具，使FPGA电路设计人员掩盖他们的子电路的功能将被开发。这些工具将使恶意设计修改变得更加困难或不可能。

Field-programmable gate arrays (FPGAs) represent an important computing infrastructure which must be protected from attackers. They are used in a wide variety of applications, including networking routers, satellites, military equipment, and automobiles, among others. The storage of FPGA programming information in memory external to the device creates a natural security weakness which, to date, has primarily been addressed via bitstream encryption. Recent work has shown that bitstream encryption is not impervious to attack and, with sufficient effort, the logical function of some or all of an FPGA design can be determined from a bitstream. This work systematically investigates advanced attacks on FPGA designs and, more importantly, develops sound countermeasures against FPGA design manipulations by determined attackers. To eliminate weaknesses, FPGA security is addressed from a new angle: the use of hardware obfuscation to make the true functionality of an FPGA design nearly indecipherable even if the entire logic-level design can be determined by bitstream reverse engineering. These questions are addressed by first developing a series of search-based computer-aided design tools which can identify security primitives (e.g. crypto primitives) in FPGA design logic-level netlists. As a result of this work, a series of automated tools which allow FPGA circuit designers to obscure the functionality of their subcircuits will be developed. These tools will make malicious design modification significantly more difficult or impossible.