Biblio

Design for Testability (DfT) techniques allow devices to be tested at various levels of the manufacturing process. Scan architecture is a dominantly used DfT technique, which supports a high level of fault coverage, observability and controllability. However, scan architecture can be used by hardware attackers to gain critical information stored within the device. The security threats due to an unrestricted access provided by scan architecture has to be addressed to ensure hardware security. In this work, a solution based on the Clock and Data Recovery (CDR) method has been presented to authenticate users and limit the access to the scan architecture to authorized users. As compared to the available solution the proposed method presents a robust performance and reduces the area overhead by more than 10%.

Digital fingerprinting refers to as method that can assign each copy of an intellectual property (IP) a distinct fingerprint. It was introduced for the purpose of protecting legal and honest IP users. The unique fingerprint can be used to identify the IP or a chip that contains the IP. However, existing fingerprinting techniques are not practical due to expensive cost of creating fingerprints and the lack of effective methods to verify the fingerprints. In the paper, we study a practical scan chain based fingerprinting method, where the digital fingerprint is generated by selecting the Q-SD or Q'-SD connection during the design of scan chains. This method has two major advantages. First, fingerprints are created as a post-silicon procedure and therefore there will be little fabrication overhead. Second, altering the Q-SD or Q'-SD connection style requires the modification of test vectors for each fingerprinted IP in order to maintain the fault coverage. This enables us to verify the fingerprint by inspecting the test vectors without opening up the chip to check the Q-SD or Q'-SD connection styles. We perform experiment on standard benchmarks to demonstrate that our approach has low design overhead. We also conduct security analysis to show that such fingerprints are robust against various attacks.

Robust and stringent fault detection and correction techniques in executing Advanced Encryption Standard (AES) are still interesting issues for many critical applications. The purpose of fault detection and correction techniques is not only to ensure the reliability of a cryptosystem, but also protect the system against side channel attacks. Such errors could result due to a fault injection attack, production faults, noise or radiation effects in deep space. Devising a proper error control mechanisms for AES cipher during execution would improve both system reliability and security. In this work a novel fault detection and correction algorithm is proposed. The proposed mechanism is making use of the linear mappings of AES round structure to detect errors in the ShiftRow (SR) and MixColumn (MC) transformations. The error correction is achieved by creating temporary redundant check words through the combined SR and MC mapping to create in case of errors an error syndrome leading to error correction with relatively minor additional complexity. The proposed technique is making use of an error detecting and correcting capability in the combined mapping of SR and MC rather than detecting and/or correcting errors in each transformation separately. The proposed technique is making use especially of the MC mapping exhibiting efficient ECC properties, which can be deployed to simplify the design of a fault-tolerance technique. The performance of the algorithm proposed is evaluated by a simulated system model in FPGA technology. The simulation results demonstrate the ability to reach relatively high fault coverage with error correction up to four bytes of execution errors in the merged transformation SR-MC. The overall gate complexity overhead of the resulting system is estimated for proposed technique in FPGA technology.