Overview of Efficient Symmetric Cryptography: Dynamic vs Static Approaches

Cryptography is the central component of a large number of security solutions. However, most of the existing algorithms do not take into consideration the structure of data, its size, the real-time constraints (latency), and the resource constraints (energy, memory, and CPU). Recently, to address these challenges, different solutions were proposed by optimizing the existing ones or by designing new lightweight algorithms. Employing a static structure requires the iteration of a round function for a large number of rounds r, which consequently leads to an increase in the latency and required resources. Therefore, in this paper, we recommend the design of new algorithms with a “dynamic structure” for symmetric key encryption towards reducing r, which in turn reduces the required latency and resources. Equally important, the substitution and diffusion primitives should become dynamic and related to a secret key. Furthermore, we present the advantages and limitations of the static and dynamic symmetric cipher approaches. The objective of this paper is to provide guidelines for the design of future (dynamic) cryptographic algorithms and highlight future research challenges, issues and directions.