FIELD: network information systems.
SUBSTANCE: during interaction between protected network devices and a server, a set of keys is formed, a manipulation table is used, a range of used keys is set, to change the keys, a random number generator is used, the number of basic cycles of the microcomputer is unique for each device, the ND identifier is determined by the difference in the number of idle cycles required to execute fictitious encryption commands, message from client to server contains a client identifier and encrypted data, pre-supplemented with a random set of characters of a certain length, message encryption is carried out by permutation of message symbols within a sliding window, the size of which is associated with the size of the key used, wherein the permutation is carried out based on the values of the successively analysed bits of such a key from the least significant to the most significant: if a certain bit of the key has a value of one, the corresponding symbols in the message are interchanged, and the effect of each bit of the key on permutation of symbols is determined by a manipulation table formed on the basis of the identifier of the ND, wherein after performing the permutation within the sliding window in the form of enumeration of all bits of the key, the latter is shifted by one symbol towards its final symbol, and when the window reaches the final symbol of the message, the window moves to the beginning of the message, then the next key from the set is selected, after which the next permutation cycle is performed, wherein the number of permutation cycles is randomly selected by the ND, wherein ND does not report number of used keys to server, after which decryption of the message on the server side is carried out by reverse manipulations with the received message based on information on the number of keys applied to the original message and padding, wherein produced message is checked for correctness by re-encryption and control over number of microcomputer cycles.
EFFECT: improved cryptographic protection of information, ensuring validation of the received message.
1 cl, 2 dwg
