A Touch of Evil: High-Assurance Cryptographic Hardware from Untrusted Components

The semiconductor industry is fully globalized and integrated circuits (ICs) are commonly defined, designed and fabricated in different premises across the world. This reduces production costs, but also exposes ICs to supply chain attacks, where insiders introduce malicious circuitry into the final products. Additionally, despite extensive post-fabrication testing, it is not uncommon for ICs with subtle fabrication errors to make it into production systems. While many systems may be able to tolerate a few byzantine components, this is not the case for cryptographic hardware, storing and computing on confidential data. For this reason, many error and backdoor detection techniques have been proposed over the years. So far all attempts have been either quickly circumvented, or come with unrealistically high manufacturing costs and complexity. This paper proposes Myst, a practical high-assurance architecture, that uses commercial off-the-shelf (COTS) hardware, and provides strong security guarantees, even in the presence of multiple malicious or faulty components. The key idea is to combine protective-redundancy with modern threshold cryptographic techniques to build a system tolerant to hardware trojans and errors. To evaluate our design, we build a Hardware Security Module that provides the highest level of assurance possible with COTS components. Specifically, we employ more than a hundred COTS secure crypto-coprocessors, verified to FIPS140-2 Level 4 tamper-resistance standards, and use them to realize high-confidentiality random number generation, key derivation, public key decryption and signing. Our experiments show a reasonable computational overhead (less than 1% for both Decryption and Signing) and an exponential increase in backdoor-tolerance as more ICs are added

Side-channel based intrusion detection for industrial control systems

Industrial Control Systems are under increased scrutiny. Their security is historically sub-par, and although measures are being taken by the manufacturers to remedy this, the large installed base of legacy systems cannot easily be updated with state-of-the-art security measures. We propose a system that uses electromagnetic side-channel measurements to detect behavioural changes of the software running on industrial control systems. To demonstrate the feasibility of this method, we show it is possible to profile and distinguish between even small changes in programs on Siemens S7-317 PLCs, using methods from cryptographic side-channel analysis.Comment: 12 pages, 7 figures. For associated code, see https://polvanaubel.com/research/em-ics/code

Smart Ticket Protection: An Architecture for Cyber-Protecting Physical Tickets Using Digitally Signed Random Pattern Markers

In order to counter forgeries of tickets for public transport or mass events, a method to validate them, using printed unique random pattern markers was developed. These markers themselves are unforgeable by their physically random distribution. To assure their authenticity, however, they have to be cryptographically protected and equipped with an environment for successful validation, combining physical and cyber security protection. This paper describes an architecture for cryptographically protecting these markers, which are stored in Aztec codes on physical tickets, in order to assure that only an authorized printer can generate a valid Aztec code of such a pattern, thus providing forge protection in combination with the randomness and uniqueness of the pattern. Nevertheless, the choice of the signature algorithm is heavily constrained by the sizes of the pattern, ticket provider data, metadata and the signature confronted by the data volume the code hold. Therefore, this paper also defines an example for a signature layout for the proposed architecture. This allows for a lightweight ticket validation system that is both physically and cryptographically secured to form a smart solution for mass access verification for both shorter to longer periods at relatively low cost.Comment: 4 pages, 2 figure