Physically unclonable cryptographic primitives using self-assembled carbon nanotubes

• Published in: Nature nanotechnology Vol. 11; no. 6; pp. 559 - 565
• Main Authors: Hu, Zhaoying, Comeras, Jose Miguel M. Lobez, Park, Hongsik, Tang, Jianshi, Afzali, Ali, Tulevski, George S., Hannon, James B., Liehr, Michael, Han, Shu-Jen
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.06.2016; Nature Publishing Group
• Subjects: 142/126; 147/135; 639/166/987; 639/301/357/73; 639/925/927/1007; Architecture; Carbon; Carbon nanotubes; Construction costs; Cryptography; Electrical properties; Electromagnetic radiation; Electronics; Hafnium oxide; Hazards; Ion exchange; Materials Science; Nanotechnology; Nanotechnology and Microengineering; Nanotubes; Organic chemistry; Power consumption; Self-assembly; Semiconductor devices; Silicon; Single wall carbon nanotubes; Transistors; Trenches; Two dimensional
• ISSN: 1748-3387; 1748-3395; 1748-3395
• DOI: 10.1038/nnano.2016.1

Information security underpins many aspects of modern society. However, silicon chips are vulnerable to hazards such as counterfeiting, tampering and information leakage through side-channel attacks (for example, by measuring power consumption, timing or electromagnetic radiation). Single-walled carbon nanotubes are a potential replacement for silicon as the channel material of transistors due to their superb electrical properties and intrinsic ultrathin body, but problems such as limited semiconducting purity and non-ideal assembly still need to be addressed before they can deliver high-performance electronics. Here, we show that by using these inherent imperfections, an unclonable electronic random structure can be constructed at low cost from carbon nanotubes. The nanotubes are self-assembled into patterned HfO 2 trenches using ion-exchange chemistry, and the width of the trench is optimized to maximize the randomness of the nanotube placement. With this approach, two-dimensional (2D) random bit arrays are created that can offer ternary-bit architecture by determining the connection yield and switching type of the nanotube devices. As a result, our cryptographic keys provide a significantly higher level of security than conventional binary-bit architecture with the same key size. Random two-dimensional arrays of carbon nanotubes, which are self-assembled via ion-exchange chemistry, can be used to create cryptographic keys by determining the connection yield and switching type of the nanotube devices.