Substitution cipher based on pseudo non-determined gamma generator.

Substitution ciphers replace symbols or other parts of the plaintext to ciphertext similar parts. Ciphers using cryptographic gamma have high security level, but a significant disadvantage is the high complexity of the operations and, consequently, much lower speed encryption versus ciphers based overlay gamma. This paper is dedicated to developed information ciphering method using gamma generator which considers the secret key and the open message. The obtained results allow increasing the ciphering speed compared with the block ciphers in ciphertext feedback and output feedback modes, meanwhile providing the cryptographic persistence which is comparable with the block ciphers persistence [ABSTRACT FROM AUTHOR]