A new Definition and Classification of Physical Unclonable Functions

A new definition of "Physical Unclonable Functions" (PUFs), the first one that fully captures its intuitive idea among experts, is presented. A PUF is an information-storage system with a security mechanism that is 1. meant to impede the duplication of a precisely described storage-functionality in another, separate system and 2. remains effective against an attacker with temporary access to the whole original system. A novel classification scheme of the security objectives and mechanisms of PUFs is proposed and its usefulness to aid future research and security evaluation is demonstrated. One class of PUF security mechanisms that prevents an attacker to apply all addresses at which secrets are stored in the information-storage system, is shown to be closely analogous to cryptographic encryption. Its development marks the dawn of a new fundamental primitive of hardware-security engineering: cryptostorage. These results firmly establish PUFs as a fundamental concept of hardware security.Comment: 6 pages, 3 figures; Proceedings "CS2 '15 Proceedings of the Second Workshop on Cryptography and Security in Computing Systems", Amsterdam, 2015, ACM Digital Librar

An overview of memristive cryptography

Smaller, smarter and faster edge devices in the Internet of things era demands secure data analysis and transmission under resource constraints of hardware architecture. Lightweight cryptography on edge hardware is an emerging topic that is essential to ensure data security in near-sensor computing systems such as mobiles, drones, smart cameras, and wearables. In this article, the current state of memristive cryptography is placed in the context of lightweight hardware cryptography. The paper provides a brief overview of the traditional hardware lightweight cryptography and cryptanalysis approaches. The contrast for memristive cryptography with respect to traditional approaches is evident through this article, and need to develop a more concrete approach to developing memristive cryptanalysis to test memristive cryptographic approaches is highlighted.Comment: European Physical Journal: Special Topics, Special Issue on "Memristor-based systems: Nonlinearity, dynamics and applicatio

Secret-free security: a survey and tutorial

Classical keys, i.e., secret keys stored permanently in digital form in nonvolatile memory, appear indispensable in modern computer security-but also constitute an obvious attack target in any hardware containing them. This contradiction has led to perpetual battle between key extractors and key protectors over the decades. It is long known that physical unclonable functions (PUFs) can at least partially overcome this issue, since they enable secure hardware without the above classical keys. Unfortunately, recent research revealed that many standard PUFs still contain other types of secrets deeper in their physical structure, whose disclosure to adversaries breaks security as well: Examples include the manufacturing variations in SRAM PUFs, the power-up states of SRAM PUFs, or the signal delays in Arbiter PUFs. Most of these secrets have already been extracted in viable attacks in the past, breaking PUF-security in practice. A second generation of physical security primitives now shows potential to resolve this remaining problem, however. In certain applications, so-called Complex PUFs, SIMPLs/PPUFs, and UNOs are able to realize not just hardware that is free of classical keys in the above sense, but completely secret-free instead. In the resulting hardware systems, adversaries could hypothetically be allowed to inspect every bit and every atom, and learn any information present in any form in the system, without being able to break security. Secret-free hardware would hence promise to be innately and permanently immune against any physical or malware-based key-extraction: There simply is no security-critical information to extract anymore. Our survey and tutorial paper takes the described situation as starting point, and categorizes, formalizes, and overviews the recently evolving area of secret-free security. We propose the attempt of making hardware completely secret-free as promising endeavor in future hardware designs, at least in those application scenarios where this is logically possible. In others, we suggest that secret-free techniques could be combined with standard PUFs and classical methods to construct hybrid systems with notably reduced attack surfaces

Public-Key Based Authentication Architecture for IoT Devices Using PUF

Nowadays, Internet of Things (IoT) is a trending topic in the computing world. Notably, IoT devices have strict design requirements and are often referred to as constrained devices. Therefore, security techniques and primitives that are lightweight are more suitable for such devices, e.g., Static Random-Access Memory (SRAM) Physical Unclonable Functions (PUFs) and Elliptic Curve Cryptography (ECC). SRAM PUF is an intrinsic security primitive that is seeing widespread adoption in the IoT segment. ECC is a public-key algorithm technique that has been gaining popularity among constrained IoT devices. The popularity is due to using significantly smaller operands when compared to other public-key techniques such as RSA (Rivest Shamir Adleman). This paper shows the design, development, and evaluation of an application-specific secure communication architecture based on SRAM PUF technology and ECC for constrained IoT devices. More specifically, it introduces an Elliptic Curve Diffie-Hellman (ECDH) public-key based cryptographic protocol that utilizes PUF-derived keys as the root-of-trust for silicon authentication. Also, it proposes a design of a modular hardware architecture that supports the protocol. Finally, to analyze the practicality as well as the feasibility of the proposed protocol, we demonstrate the solution by prototyping and verifying a protocol variant on the commercial Xilinx Zynq-7000 APSoC device

Energy efficient mining on a quantum-enabled blockchain using light

We outline a quantum-enabled blockchain architecture based on a consortium of quantum servers. The network is hybridised, utilising digital systems for sharing and processing classical information combined with a fibre--optic infrastructure and quantum devices for transmitting and processing quantum information. We deliver an energy efficient interactive mining protocol enacted between clients and servers which uses quantum information encoded in light and removes the need for trust in network infrastructure. Instead, clients on the network need only trust the transparent network code, and that their devices adhere to the rules of quantum physics. To demonstrate the energy efficiency of the mining protocol, we elaborate upon the results of two previous experiments (one performed over 1km of optical fibre) as applied to this work. Finally, we address some key vulnerabilities, explore open questions, and observe forward--compatibility with the quantum internet and quantum computing technologies.Comment: 25 pages, 5 figure