Aiming at the increasing demand of the network security,based on the IPSec protocol and the chaotic cryptosystem technology,a new network security framework which was running on the Linux platform and integrating with the chaotic cryptosystem was proposed.

As a novel technology in cryptography,digital chaotic cipher has attracted researcher dense interest and widely study.

In this paper the authors analysis the law of information leak of self-synchronous chaotic ciphers,hereby present a divide-and-conquer attack to self-synchronous chaotic ciphers,which is the first attack of this kind in this area.

In this paper, taking the ZLL chaotic stream cipher as example, the problem of equivalent keys of chaotic cipher is studied.

In this paper we survey the new advances in the research on computer cipher, focusing on block cipher, sequence cipher, public key cipher and chaos cipher.

This paper presented a scheme to improve the real time performance and local complexity of the chaotic stream cipher based on piecewise linear maps.

Aiming at the characteristic that the document transmiting must be reliability and security,generalizes three schemes of digital signature in e-government,and then presents a scheme of digital signature based on hybrid cryptosystem.

Against the problem of the security and complexity of the electronic document, we propose a method of combining the hybrid cryptosystem and digital signature, and for the practicality and flexility, We use the technique of component object model We integrate seamlessly this system into the microsoft word softwar

For a detailed analysis, it studies principles and the process of the authentication mechanisms as the initiative to attack, as well as passive attacks on the encryption mechanism, which focuses on a data encryption technologies-hybrid cryptosystem.