THE METHOD OF INCREASING THE EFFICIENCY OF SYMMETRICAL BLOCK ENCRYPTION

Abstract

Ensuring data safety and security are relevant in any sphere of human activity, which is directly related to the implementation of modern and advanced symmetric and asymmetric algorithms and methods of cryptographic protection of information. One of the well-known and safe encryption algorithms, known as AES (Advanced Encryption Standard), which is endowed with the properties of ease of practical implementation and high reliability, has found its wide application for block symmetric data encryption. A feature of symmetric encryption is the processing of large amounts of information, the use of the same key for encryption and decryption, high reliability of data protection. This paper proposes to improve this algorithm to provide faster data processing. All modifications of the AES transformations do not reduce the high cryptographic strength of the cipher, and their principles are described in detail in the paper. This practical implementation of the optimized algorithm shows the possibility of combining a number of mathematical operations that have a similar principle of processing elements, which allowed to reduce the processing time. In addition, in the improved implementation the MixColumns operation uses pre-calculated lookup tables of the required value, which also helps to increase the speed of transformations but at the cost of more memory for the code size. A comparative analysis of the practical implementation of the standard and optimized AES cryptoalgorithms has been carried out, and numerical indicators of the processing time of test data have been obtained, which are presented in the form of tables. Graphs of the dependence of the encryption and decryption procedure execution time on the file size for the standard and optimized AES algorithms have been constructed. The results show a significant percentage of optimization - up to 50% for encryption and up to 75% for decryption of data.