Algebraic Security Analysis of Key Generation with Physical Unclonable Functions

Physical Unclonable Functions (PUFs) provide cryptographic keys for embedded systems without secure non-volatile key storage. Several error correction schemes for key generation with PUFs were introduced, analyzed and implemented over the last years. This work abstracts from the typical algorithmic level and provides an algebraic view to reveal fundamental similarities and differences in the security of these error correction schemes. An algebraic core is introduced for key generation with Physical Unclonable Functions (PUFs). It computes the secret key through the helper data from the input PUF response and an optional random number. For nearly uniformly distributed PUF responses, the leakage of the secret key and the helper data can be brought to zero if and only if the rank of the algebraic core is equal to the sum of the ranks of the key generating part and the rank of the helper data generating part. This rank criterion has the practical advantage that a security check can be performed for linear codes at an early design stage of an algorithm. The criterion is applied to state-of-the-art approaches to show that fuzzy commitment and systematic low leakage coding are the only analyzed schemes that achieve zero leakage

Roadmap on optical security

Postprint (author's final draft

09031 Abstracts Collection -- Symmetric Cryptography

From 11.01.09 to 16.01.09, the Seminar 09031 in ``Symmetric Cryptography \u27\u27 was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Multiply Constant-Weight Codes and the Reliability of Loop Physically Unclonable Functions

We introduce the class of multiply constant-weight codes to improve the reliability of certain physically unclonable function (PUF) response. We extend classical coding methods to construct multiply constant-weight codes from known $q$-ary and constant-weight codes. Analogues of Johnson bounds are derived and are shown to be asymptotically tight to a constant factor under certain conditions. We also examine the rates of the multiply constant-weight codes and interestingly, demonstrate that these rates are the same as those of constant-weight codes of suitable parameters. Asymptotic analysis of our code constructions is provided

Photonic Physical Unclonable Functions: From the Concept to Fully Functional Device Operating in the Field

The scope of this paper is to demonstrate a fully working and compact photonic Physical Unclonable Function (PUF) device capable of operating in real life scenarios as an authentication mechanism and random number generator. For this purpose, an extensive experimental investigation of a Polymer Optical Fiber (POF) and a diffuser as PUF tokens is performed and the most significant properties are evaluated using the proper mathematical tools. Two different software algorithms, the Random Binary Method (RBM) and Singular Value Decomposition (SVD), were tested for optimized key extraction and error correction codes have been incorporated for enhancing key reproducibility. By taking into consideration the limitations and overall performance derived by the experimental evaluation of the system, the designing details towards the implementation of a miniaturized, energy efficient and low-cost device are extensively discussed. The performance of the final device is thoroughly evaluated, demonstrating a long-term stability of 1 week, an operating temperature range of 50C, an exponentially large pool of unique Challenge-Response Pairs (CRPs), recovery after power failure and capability of generating NIST compliant true random numbers

AUTHENTICATED KEY ESTABLISHMENT PROTOCOL FOR CONSTRAINED SMART HEALTHCARE SYSTEMS BASED ON PHYSICAL UNCLONABLE FUNCTION

Smart healthcare systems are one of the critical applications of the internet of things. They benefit many categories of the population and provide significant improvement to healthcare services. Smart healthcare systems are also susceptible to many threats and exploits because they run without supervision for long periods of time and communicate via open channels. Moreover, in many implementations, healthcare sensor nodes are implanted or miniaturized and are resource-constrained. The potential risks on patients/individuals’ life from the threats necessitate that securing the connections in these systems is of utmost importance. This thesis provides a solution to secure end-to-end communications in such systems by proposing an authenticated key establishment protocol. The main objective of the protocol is to examine how physical unclonable functions could be utilized as a lightweight root of trust. The protocol’s design is based on rigid security requirements and inspired by the vulnerability of physical unclonable function to machine learning modeling attacks as well as the use of a ratchet technique. The proposed protocol verification and analysis revealed that it is a suitable candidate for resource-constrained smart healthcare systems. The proposed protocol’s design also has an impact on other important aspects such as anonymity of sensor nodes and gateway-lose scenario