Due to increase in threats posed by offshore foundries, the companies outsourcing IPs are forced to protect their designs from the threats posed by the foundries. Few of the threats are IP piracy, counterfeiting and reverse engineering. To overcome these, logic encryption has been observed to be a leading countermeasure against the threats faced. It introduces extra gates in the design, known as key gates which hide the functionality of the design unless correct keys are fed to them. The scan tests are used by various designs to observe the fault coverage. These scan chains can become vulnerable to sidechannel attacks. The potential solution for protection of this vulnerability is obfuscation of the scan output of the scan chain. This involves shuffling the working of the cells in the scan chain when incorrect test key is fed. In this paper, we propose a method to overcome the threats posed to scan design as well as the logic circuit. The efficiency of the secured design is verified on ISCAS’89 circuits and the results prove the security of the proposed method against the threats posed.

Although self-modifying code has been shyed away from due to its complexity and discouragement due to safety issues, it nevertheless provides for a very unique obfuscation method and a different perspective on the relationship between data and code. The generality of the von Neumann architecture is hardly realized by today’s processor models. A code-only model is shown where every instruction merely modifies other instructions yet achieves the ability to compute and Turing machine operation is easily possible.

The article is devoted to generation techniques of the new public key crypto-systems, which are based on application of indistinguishability obfuscation methods to selected private key crypto-systems. The techniques are applied to symmetric key crypto-system and the target system is asymmetric one. As an input for our approach an implementation of symmetric block cipher with a given private-key is considered. Different obfuscation methods are subjected to processing. The targetsystem would be treated as a public-key for newly created public crypto-system. The approach seems to be interesting from theoretical point of view. Moreover, it can be useful for information protection in a cloud-computing model.