Research And Implementation Of Small-scale Local Area Network Printing Audit System

With the development of information technology,network printing has become the mainstream print mode in small-scale LAN.However,as the network printing becomes popular,problems concerning security are also exposed,which includes a waste of printing and printing leakage of secret.Printing Audit existing products in the Windows system can achieve quite good printing audit effects,while due to the different core between Windows and Unix-like system,these products cannot be used in Unix-like system.With the widespread use of Unix-like system,research in support for printing audit system in multiple operating systems is necessary.This paper begins with the introduction of the research background and significance of the system and then clarifies the major functions of printing audit system.Then the paper presents the research status of printing audit techniques.To overcoming the deficiencies of the current techniques,the paper proposes a scheme based on CUPS print auditing techniques,and designs as well as implements a printing audit system capable of supporting multiple operating systems.Detailed test is also taken to check it.The main work of this paper are the following points:1.First,the basic principles of printing and related knowledge are introduced,the Windows system print systems and related printing audit techniques are analyzed.Its advantages and disadvantages are pointed out.Then it analyzes the printing process of Unix-like systems,focusing on the composition of IPP protocol and principles of CUPS,then the advantages and disadvantages of the CUPS are pointed out.2.A printing audit scheme based on CUPS capable of supporting for multiple operating systems is proposed and the CUPS is perfected.Firstly,by means of CUPS as a print server,support for multiple operating systems is effectuated,meanwhile which improves the security of the system.Then through the analysis and experiment of the DHCP protocol,SNMP protocol and CUPS the API,a mechanism capable of automatically adding a printer is effectuated,which is faster and more accurate compared with the original CUPS manual mode.3.Combined with the actual demand in printing audit,the hostname,IP and MAC of the client is obtained by making use of CUPS API and ARP tools,the print permissions of the unregistered host is limited by using the mechanism of white list,the pages of the print job is extracted by utilizing Ghostpdl and Unix system tools,and the problem of inaccurate statistics of the pages of print job and incomplete authentication mechanism during the printing audit process of multiple operating systems of CUPS is solved.Besides,by virtue of PostScript language programming technology,mandatory addition of watermark function is achieved,the pattern matching algorithm is studied and the application of Sunday algorithm in Chinese environment is improved.4.A user-friendly web management system is designed and implemented,which is convenient for the management of printing jobs and personnel as well as the setting up of security policies.Meanwhile,the design and implementation of the major module of the underlying sub audit system is introduced.Finally,the function and performance of the system is tested and the technical feasibility is verified.This paper has the following innovations:1.Unlike the current technique,the paper provides a new way for the print audit techniques:by means of sharing print server via CUPS to get print job data,support for multiple operating systems is secured.2.CUPS is improved to add print audit functions such as identity authentication,limit of the pages of the print job,print content storage and retrieval,forced watermark that would not be fulfilled by CUPS in the multi-system environment.3.The application of Sunday algorithm in Chinese environment is improved.In certain extent,the number of matches is reduced,the efficiency of the algorithm is elevated.The improved algorithm can also be applied in other field of Chinese retrieval.