Server-Based Access Verification.

In many practical contexts, it is necessary to certify that the content of a web server log file is correct with respect to real client traffic. This certification should be carried out by an independent third party, which we will call a certification agency, that is trusted by the web server owner and by the log file user. The certification agency should use adequate technology to perform the requested certification. The used technology must ensure that the log file was not altered or, in case of modifications to the log file, it should detect individual items that were added or removed. In this paper a novel technique for web server access certification based on software is presented, and its reliability and performance is discussed. A case study and experimental data from a web site with significant traffic is also presented.