Biblio

Networks have evolved very rapidly, which allow secret data transformation speedily through the Internet. However, the security of secret data has posed a serious threat due to openness of these networks. Thus, researchers draw their attention on cryptography field for this reason. Due to the traditional cryptographic techniques which are vulnerable to intruders nowadays. Deoxyribonucleic Acid (DNA) considered as a promising technology for cryptography field due to extraordinary data density and vast parallelism. With the help of the various DNA arithmetic and biological operations are also Blum Blum Shub (BBS) generator, a multi-level of DNA encryption algorithm is proposed here. The algorithm first uses the dynamic key generation to encrypt sensitive information as a first level; second, it uses BBS generator to generate a random DNA sequence; third, the BBS-DNA sequence spliced with a DNA Gen Bank reference to produce a new DNA reference. Then, substitution, permutation, and dynamic key are used to scramble the new DNA reference nucleotides locations. Finally, for further enhanced security, an injective mapping is established to combine encrypted information with encrypted DNA reference using Knight tour movement in Hadamard matrix. The National Institute of Standard and Technology (NIST) tests have been used to test the proposed algorithm. The results of the tests demonstrate that they effectively passed all the randomness tests of NIST which means they can effectively resist attack operations.

Scan design is a universal design for test (DFT) technology to increase the observability and controllability of the circuits under test by using scan chains. However, it also leads to a potential security problem that attackers can use scan design as a backdoor to extract confidential information. Researchers have tried to address this problem by using secure scan structures that usually have some keys to confirm the identities of users. However, the traditional methods to store intermediate data or keys in memory are also under high risk of being attacked. In this paper, we propose a dynamic-key secure DFT structure that can defend scan-based and memory attacks without decreasing the system performance and the testability. The main idea is to build a scan design key generator that can generate the keys dynamically instead of storing and using keys in the circuit statically. Only specific patterns derived from the original test patterns are valid to construct the keys and hence the attackers cannot shift in any other patterns to extract correct internal response from the scan chains or retrieve the keys from memory. Analysis results show that the proposed method can achieve a very high security level and the security level will not decrease no matter how many guess rounds the attackers have tried due to the dynamic nature of our method.