Analysis of Stream Modes for Block Symmetric Ciphers

For cryptographic protection of informational resources and technologies the block symmetric ciphering is being used, which consists in modification of information by using of special (key) data in order to hide/reconstruct the information, to validate its verity, integrity, authorship etc. The ensured stability level depends not only on properties of used cipher, but also on way of its utilization, i.e. the properties of the cryptographic conversion depend immediately on the utilization mode of the block symmetric ciphering. As a ciphering mode is usually understood such a utilization method of the block symmetric cipher, which enables realizing of the sequence conversion of blocks of open data into a sequence of blocks with ciphered data, while getting of certain preset cryptographic properties. In this chapter are presented the researches results of stream modes utilization of block symmetric ciphers.