Printable Epsilon‐Type Structure Transistor Arrays with Highly Reliable Physical Unclonable Functions

Abstract

With rapid development of emerging applications, especially the artificial intelligence and Internet of Things (IoT), a large amount of digital information needs to be replicated, stored, processed, and communicated. This in turn requires secure communication and/or authentication; for this, cryptographic keys are required. [1,2] Software-based data encryption methods based on pseudorandom number generators are no longer sufficient due to their vulnerability; encryption effectiveness is also affected by the key quality. [3] These concerns essentially force the future data-intensive applications to have builtin-hardware-based information security systems, rather than relying solely on the software for battling security attacks. However, traditional hardware encryption solutions often work by storing the keys used by different encryption algorithms in a nonvolatile memory array; the stored cryptographic keys are vulnerable to physical and side-channel attacks, such as by observing the power consumed or radiation emitted. [4] Therefore, an epochmaking hardware-security technology is urgently needed for the future technologies.Physical unclonable functions (PUFs), also known as the physical one-way functions, [5] are promising hardware security primitives that allow random, unique cryptographic keys to be extracted for different application scenarios, rather than being stored in nonvolatile memory arrays. PUFs utilize intrinsic manufacturing defects in the physical microstructure of hardware components to interact with different external stimuli (light, voltage, and magnetic field), to produce unclonable cryptographic primitives comparable to biometrics for hardware security authorization. [6] The first reported PUFs exploited specific 2D patterns generated by a nonuniform 3D structure being optically hashed. [5] In general, optical PUF requires bulky external equipment and is incompatible with the existing silicon fabrication processes, which hinders its further application. [7] Additionally, conventional silicon PUFs suffer from issues such as low entropy, susceptibility to noise interference, and inability to resist machine-learning (ML) attacks. [8,9] In recent years, several PUFs constructed using novel materials, such Printed electronics promises to drive the future data-intensive technologies, with its potential to fabricate novel devices over a large area with low cost on nontraditional substrates. In these emerging technologies, there exists a large digital information flow, which requires secure communication and authentication. Physical unclonable functions (PUFs) offer a promising builtin hardware-security system comparable to biometrical data, which can be constructed by device-specific intrinsic variations in the additive manufacturing process of active devices. However, printed PUFs typically exploit the inherent variation in layer thickness and roughness of active devices. The current in devices with enough significant changes to increase the robustness to external environment noise is still a challen...

Ultradurable Embedded Physically Unclonable Functions

“…(c) Flame and pressurized water stability tests of ultradurable embedded PUFs. (d) Comparison of the thermal stability of PUFs with the literature. ,,,,− …”

Physical Unclonable Functions Based on Photothermal Effect of Gold Nanoparticles

“…The total authentication error probability (TAEP), involving the false-negative rate (FNR), and false-positive rate (FPR), is widely used to estimate PUF security levels. , As illustrated in Figure e, the FNR represents the probability of incorrect rejection of a valid PUF, whereas the FPR denotes the probability of incorrect acceptance of an invalid PUF. ,− Authentication is accepted only if the HD between the examined and registered responses is less than the authentication threshold. To minimize the TAEP of PT–PUF, we chose an optimized threshold of 0.217 for authentication.…”

“…The reasonable choice of entropy source is crucial for the construction of high security level PUFs. According to the type of entropy source, PUFs are categorized into different types, such as electrical PUFs and optical PUFs. − Optical PUFs have gained increased attention due to high contrast responses and encoding capacity since Pappu et al proposes the concept of PUF in 2002. − Scattering PUFs, such as laser scattering patterns , and localized surface plasmon resonance (LSPR) of metal nanoparticles , are modulated by the laser parameters and the geometry of nanoparticles. However, the scattering PUFs are unreliable due to the sensitivity to the fluctuation of excitation .…”

Heteronanostructured Field-Effect Transistors for Enhancing Entropy and Parameter Space in Electrical Unclonable Primitives

“…In this respect, electrical PUFs using non-silicon nanomaterials have been actively studied. − A variety of nanomaterials as entropy sources have been employed in different types of electronic devices, including transistors, FETs, resistors, and memristors (Table S1). Notable constituent nanomaterials include poly­[(2,5-bis­(2-octyldodecyl)-3,6-bis­(thien-2-yl)-pyrrolo­[3,4- c ]­pyrrole-1,4-diyl)- co -(2,2′-(2,1,3-benzothiadiazole)]-5,5′-diyl)] (PODTPPD-BT), 2,8-difluoro-5,11-bis­(triethylsilylethynyl) anthradithiophene (diF-TESADT), indium oxide, indium tin oxide (ITO), silicon nanowires, propyl pyridinium lead iodide (PrPyr­[PbI 3 ]), hafnium­(IV) oxide, , Ta/CoFeB/MgO, germanium–antimony–tellurium (GaSbTe), poly­(styrene- b -methyl methacrylate) and hydroxyl-terminated P­(S-r-MMA) random copolymer, a mixture of octadecyltrichlorosilane and 1 H ,1 H ,2 H ,2 H -perfluorodecyltriethoxysilane (ODTS/PFOTES), carbon nanotubes (CNTs), ,,, and graphene. , However, these electrical PUFs based on nanomaterials possess a restricted parameter space, often limited to a single challenge–response pair.…”

“…Insufficient randomness with low entropy is often associated with output responses that follow a Gaussian distribution in a predictable manner. A single challenge–response pair in the existing transistor-based electrical PUFs using 2D TMDCs increases vulnerability to external attacks; field effect transistor (FET)-based PUFs using bare MoS 2 or WS 2 are intrinsically disadvantaged to enhance the parameter space, due to the limited measurements of gate voltage and drain current. ,,− It should be noted that an enhanced parameter space is of paramount importance in deployable and scalable PUFs. − Unfortunately, other electrical PUFs using nanomaterials and nanostructures − have a limited parameter space (see Table S1 of Supporting Information for comprehensive comparisons).…”