Privatelink.de uses the Double Forward Strategy for the anonymisation of links. To verify the reliability of this strategy, we made a benchmark evaluation of four link anonymisation services.
The revised services are:
The benchmark idea can be summarized as follows: create an extra page for every anonymizer. Forward visitors to their pages and to use the corresponding anonymizer for this. Save information on the transmitted referers. Evaluate the results.
Thus the results are comparable among themselves, the visitors should come from the same source. In addition, the source should guarantee a wide dispersion of browser versions. So that we can state that the anonymisation service works for all and not only with a certain browser software. A visitor exchange is a good possibility for this purpose.
We considered to use one of the most advanced counter systems to track information about the visitors: Google-Analytics. For each anonymizer we created its own counter, and a corresponding HTML file. Each file was placed on a separate domain to avoid interference between the cookies, that will be set for the referer tracking.
There are the following paths for the visitors:
- Source (visitor exchange) -> privatelink.de/?testdomain1/google_privatelink.de.html -> testdomain1/google_privatelink.de.html
- Source (visitor exchange) -> anonym.to/?testdomain2/google_anonym.to.html -> testdomain2/google_anonym.to.html
- Source (visitor exchange) -> anonymlink.net/?testdomain3/google_anonymlink.net.html -> testdomain3/google_anonymlink.net.html
- Source (visitor exchange) -> acab.in/?testdomain4/google_acab.in.html -> testdomain4/acab.in.html
The test ran 8 days with a constant influx of visitors. Each page got at least 35 000 visitors in this time.
The graph on the right side shows the anonymising rate (in percentage). The bars are composed of the completely anonymous requests (referer is empty) and the calls for which the original referer has been overwritten by anonymous URL. The differences in calling behavior depends on the different treatment of transfers in different browsers.
The anonymization service Privatelink.de delivers a complete anonymity and hides the referer reliably at 100% of the visitors. This completes the proof of efficacy.