Abstract
To be secure, modern information and communication technology (ICT) needs reliable encryption. Symmetric cryptography combines encryption algorithms that use the same cryptographic keys for both encryption of plaintext and decryption of ciphertext. These algorithms are used for confidentiality ensuring in different spheres but most of them are worn out and outdated. Modern encryption algorithms development is very actual task for ICT (up to date and next generation). In this paper to improve the security effectiveness of electronic information resources, two encryption algorithms have been developed based on fixed lookup tables with extended-bit depth and dynamic key-dependent lookup tables. The developed algorithms are at least two times faster than the previous national encryption standard and virtually secure to linear and differential cryptanalysis. Properties of random sequences formed using the proposed algorithms’ encryption (in counter mode) were explored in the environment of NIST STS statistical tests, according to which they passed integrated control by mentioned tests with better results than other generators.