Usage of non-commutative two-operand CET-operations in limited resources stream ciphers

Abstract

Primary research task: to develop and evaluate different scenarios of utilizing the limited resources stream encryption based on noncommutative CET-operations; to develop and scientifically justify the structure of the devices applicable to the execution of encryption scenarios. The object of research: processes of data transformation in the limited resource stream ciphers based on CET-operations. We have used the hypothesis claiming that it is possible to improve the stream encryption systems if there is an option to permutate operands in both the commutative and non-commutative CET-operations as the foundation of our research. We have also defined and formalized the six groups of two-operand CET- operations allowing the permutation of operands to solve tasks according to the introduced classification. The attributes of the six groups mentioned above influence the data transformation process in stream ciphers. In addition, we have also defined the three possible scenarios of stream encryption, including their limitations, which consider the usage of the aforementioned groups of CET-operations. The provided examples combined with the results of modeling the processes of data transformation allow us to prove the operating efficiency of cryptographic systems in different encryption scenarios. The introduced and analyzed structures of devices based on the aforementioned stream encryption scenarios also reflect the attributes of their technical implementation. By examining the created models and the aforementioned devices for executing the stream encryption scenarios, we have defined the most prominent development paths for the limited resources stream encryption and created the foundation for their future improvement. The results of our analysis prove that all three scenarios have their own positive and negative aspects. For example, we suggest using the first and the third stream encryption scenarios in a single device during the practical implementation. This option suits the scenarios we have researched since it provides the best diversity of encryption algorithms with minimal complexity and a maximal number of substitution tables. We have defined mobile and stationary systems of limited resources cryptographic security of the confidential data as the most suitable branch for the application of the acquired results.