6.2.3 Encore

Researchers caused people’s computers to secretly visit websites that were potentially blocked by repressive governments.

In March 2014, Sam Burnett and Nick Feamster launched Encore, a system to provide real-time and global measurements of Internet censorship. To do this, the researchers, who were at Georgia Tech, encouraged website owners to install this small code snippet into the source files of their web pages:

<iframe src="//encore.noise.gatech.edu/task.html" 
        width="0" height="0"
        style="display: none"></iframe>

If you happen to visit a web page with this code snippet in it, your web browser will try to contact a website that the researchers were monitoring for possible censorship (e.g., the website of a banned political party). Then, your web browser will report back to the researchers about whether it was able to contact the potentially blocked website (figure 6.2). Further, all of this will be invisible unless you check the HTML source file of the web page. Such invisible third-party page requests are actually quite common on the web (Narayanan and Zevenbergen 2015), but they rarely involve explicit attempts to measure censorship.

Figure 6.2: Schematic of the research design of Encore (Burnett and Feamster 2015). The origin website has a small code snippet embedded in it (step 1). Your computer renders the web page, which triggers the measurement task (step 2). Your computer attempts to access a measurement target, which could be the website of a banned political group (step 3). A censor, such as a government, may then block your access to the measurement target (step 4). Finally, your computer reports the results of this request to the researchers (not shown in the figure). Reproduced by permission from Burnett and Feamster (2015), figure 1.

This approach to measuring censorship has some very attractive technical properties. If a sufficient number of websites include this simple code snippet, then Encore can provide a real-time, global-scale measure of which websites are censored. Before launching the project, the researchers conferred with their IRB, which declined to review the project because it was not “human subjects research” under the Common Rule (the set of regulations governing most federally funded research in the United States; for more information, see the historical appendix at the end of this chapter).

Soon after Encore was launched, however, Ben Zevenbergen, then a graduate student, contacted to the researchers to raise questions about the ethics of the project. In particular, Zevenbergen was concerned that people in certain countries could be exposed to risk if their computer attempted to visit certain sensitive websites, and these people did not consent to participate in the study. Based on these conversations, the Encore team modified the project to attempt to measure the censorship of only Facebook, Twitter, and YouTube because third-party attempts to access these sites are common during normal web browsing (Narayanan and Zevenbergen 2015).

After collecting data using this modified design, a paper describing the methodology and some results was submitted to SIGCOMM, a prestigious computer science conference. The program committee appreciated the technical contribution of the paper, but expressed concern about the lack of informed consent from participants. Ultimately, the program committee decided to publish the paper, but with a signing statement expressing ethical concerns (Burnett and Feamster 2015). Such a signing statement had never been used before at SIGCOMM, and this case has led to additional debate among computer scientists about the nature of ethics in their research (Narayanan and Zevenbergen 2015; B. Jones and Feamster 2015).