Biblio

Blockchain technology is the cornerstone of digital trust and systems' decentralization. The necessity of eliminating trust in computing systems has triggered researchers to investigate the applicability of Blockchain to decentralize the conventional security models. Specifically, researchers continuously aim at minimizing trust in the well-known Public Key Infrastructure (PKI) model which currently requires a trusted Certificate Authority (CA) to sign digital certificates. Recently, the Automated Certificate Management Environment (ACME) was standardized as a certificate issuance automation protocol. It minimizes the human interaction by enabling certificates to be automatically requested, verified, and installed on servers. ACME only solved the automation issue, but the trust concerns remain as a trusted CA is required. In this paper we propose decentralizing the ACME protocol by using the Blockchain technology to enhance the current trust issues of the existing PKI model and to eliminate the need for a trusted CA. The system was implemented and tested on Ethereum Blockchain, and the results showed that the system is feasible in terms of cost, speed, and applicability on a wide range of devices including Internet of Things (IoT) devices.

Timing slacks possibly lead to reliability issues and/or security vulnerabilities, as they may hide small delay defects and malicious circuitries injected during fabrication, namely, hardware Trojans. While possibly harmless immediately after production, small delay defects may trigger reliability problems as the part is being used in field, presenting a significant threat for mission-critical applications. Hardware Trojans remain dormant while the part is tested and validated, but then get activated to launch an attack when the chip is deployed in security-critical applications. In this paper, we take a deeper look into these problems and their underlying reasons, and propose a design technique to maximize the detection of small delay defects as well as the hardware Trojans. The proposed technique eliminates all slacks by judiciously inserting delay units in a small set of locations in the circuit, thereby rendering a simple set of transition fault patterns quite effective in catching parts with small delay defects or Trojans. Experimental results also justify the efficacy of the proposed technique in improving the quality of test while retaining the pattern count and care bit density intact.