Efficient & secure cipher scheme with dynamic key-dependent mode of operation

International audienceSecurity attacks are constantly on the rise leading to drastic consequences. Several security services are required more than ever to prevent both passive and active attacks such as Data Confidentiality (DC). A DC security service is typically based on a strong symmetric cipher algorithm. However, some of today’s applications, such as real-time applications and those running on constrained devices, require efficient lightweight cipher schemes that can achieve a good balance between the security level and system performance. Recently, a set of lightweight cryptographic algorithms has been proposed to that end, which is based on a dynamic key approach. The dynamic structure enables the reduction of the number of rounds to the minimum possible value of just one or two rounds, which minimizes the computational overhead without degrading the security level. This paper follows the dynamic key-dependent cipher logic and proposes a new flexible lightweight technique with or without the reliance on the chaining mode of operation. Furthermore, the dynamic key changes for each input message, which leads to different cipher primitives such as substitution and permutation tables, in addition to round keys. Also, the proposed mode of operation is based on the dynamic key approach whereby blocks are selected and mixed according to a dynamic permutation table. Accordingly, different plaintext messages are encrypted differently while preserving the avalanche effect. Finally, we conduct security and performance analysis to validate the efficiency and robustness of the proposed cipher scheme as compared to traditional ciphers and to the recently proposed dynamic key-dependent ciphers