Advanced encryption standard (AES) crypto-algorithm design can be implemented in software and hardware. No known attacks are available that can break the AES with brute force or cryptanalysis in finite time. However, when the AES is implemented in hardware, test infrastructure such as scan chain, stimuli decompressor, response compactor and built-in self-test (BIST) are included in the normal design for making the crypto-chip easily testable after manufacturing. This test infrastructure is highly susceptible to attacks. The attacker may misuse the scan-chain content for the retrieval of secret key from AES hardware. In this study, the authors investigated scan-chain attack based on different distributions of key-related flip-flops of AES hardware implementation with X-tolerant response compactor-based test infrastructure. The modular exponentiation security scheme as a counter measure against test infrastructure attacks is proposed. In this study, the statistical security analyses are performed with and without the proposed countermeasure in case of AES hardware followed by X-tolerant test response compactor. The experimental result shows that the proposed countermeasure thwarts the attack with almost constant rate for different distributions of key-related flops in the scan-chain, and hence it is not dependent on the nature of scan-chain architecture design.

Cryptocurrencies have been broadly scrutinised in recent times for a host of concerning regulatory and cybercriminality issues. Although steps have been taken to promote regulatory sufficiency in the near future, we examine the avenues through which this extremely high-risk industry can derive potentially devastating contagion channels, influencing both unwilling and unsuspecting investors. We focus this research on the expressions of interest by publicly traded companies across the world to utilise cryptocurrency and blockchain projects. We find evidence that there exists a substantial stock price premium and sustained increase in volatility in the aftermath of blockchain announcements, with emphasis on highly-speculative motives such as coin creation and corporate name changes. Changes in price discovery and information flows are found to be largely determined from cryptocurrency-based pricing sources in the aftermath of speculative announcements. We discuss the inherent ethical and legal issues, considering as to whether such announcements are simply an attempt to artificially manipulate share prices and take part in the current phase of crypto-exuberance.