1- Symmetric (Secret-key) cryptosystems  where only one key is used for both encryption and decryption operations, and it is of two types: Block ciphers and stream ciphers
Wu, Cryptanalysis and Design of Stream Ciphers
also are extensively studied in the cryptographic environment due to its quicker execution; however, they're vulnerable to attacks as compared to SP network block ciphers.
are suitable for the larger data than the block cipher methods.
A certain number of reported encryption approaches jointly employ elements of traditional stream ciphers
and elements of coding theory as well as features of certain communication channels (see, e.
operate on abit stream of arbitrary length, e.
Native stream ciphers
perform faster operations than block cipher , yet many of them are considered broken due to various attacks, especially on the keystream .
The International Organization for Standardization (ISO) and the International Electro technical Commission (IEC) have been working on ISO/IEC 29192 as an international standard for light-weight cryptography for implementation in constrained environments and have now issued ISO/IEC 29192-3, the section on stream ciphers
, adopting Enocoro as an international standard.
In recent years, the stream ciphers
MULTI-S01(6) and MUGI(7) in 2005, and the public key cipher HIME(R)(8) in 2006, have been adopted as international standards.
are much less power consuming, requires small space for their operations and are faster in operation than other cryptographic algorithms.
can be categorized into two categories: hardware-based and software-based.
l high encryption rate of the Y-00 protocol is demonstrated experimentally, a security analysis on the Yuen-2000 protocol against the fast correlation attack, the typical attack on stream ciphers
, is presented (Corndorf et al.