Description: The article summarizes the mathematical model of indirect encryption keys using a set of fixed length. The analysis of the current situation in the development of new cryptographic techniques to protect the information provides some guidance on the development of new methods of encryption. Showing the method of indirect communication with the class of undisclosed encryption ciphers. We describe the encryption and decryption, as well as some features of the formation used by a subset of fixed keys.
Keywords: encryption, decryption, cryptography, indirect encryption, cipher with the perfect secrecy property