A divide-and-conquer attack on the stream cipher which could decrease entropy of the key efficiently is proposed.

By analyzing the linear congruent algorithm on a prime field of CCPRSEA,it gains chaotic sequence and gives a tally-degree-based divide-and-conquer attack algorithm by using the information leak of the chaotic map itself.

This paper analyzes the security of the chaos-based feedback cryptographic scheme of human video objects and gives a divide-and-conquer attack algorithm against it by using the incompleteness of which the key information diffuses in keystreams.

Text-Independent Writer Identification based on Optimized Segmentation and Reconstructed Handwriting Image;

The improvement of 6 round and 8 round DES of differential attack and its implement;

Experimental results show that the improved algorithm has stronger ability to resist differential attack,and the avalanche effect of .

Some kinds of the precaution for protecting the Rijndael algorithm against the differential attack is proposed.

A new detectionoriented attack classification approach——DetectClass, based on the data collected directly by the intrusion detection system (IDS), is proposed.

A new attack classification method was put forward and delivered the criterion and results of the classification.

In order to overcome the disadvantages that IDS evaluation need a great deal of handwork,on account with an attack classification based on connection,APC Class,this paper puts forward an adaptative test model that facilitate simulating attack.