MSc-IT Study Material
June 2010 Edition

Computer Science Department, University of Cape Town

Censorship Strategies

Overview

We investigated the use of metadata in an earlier unit. It is often this data that is used to automatically determine whether a site should be blocked or not. It is also possible for sites to be added to lists of unacceptable or acceptable sites. Some of the popular systems for censoring sites are discussed below.

Blocking Software

Blocking software contains a list of "objectionable" sites which it does not allow the Web browser to access. This list can be updated at the user's discretion. For example, parents may want to allow certain sites to be accessed by their children as they grow older and mature.

Surfwatch and Netnanny are examples of such software.

A new alternative is being developed: instead of restricting access to "bad" sites, the software keeps a list of "good" sites to which access is allowed. However, this might be very restrictive as keeping an exhaustive list of "good" sites is difficult, and so many appropriate sites may be blocked.

Activity 2: Investigating Blocking Software

Use your favourite Internet search engines to look for blocking software. NetNanny might be a good place to start. Focus on what the software claims to do. Note your opinion of each feature and whether you think it is a good idea. Can you offer a better way to achieve this protection?

Ratings

Website content can be classified according to certain labels, similar to those used by the Film and Video Classifications. The Platform for Internet Content Selection (PICS) is a well-known classification rating system that has been developed by the World Wide Web Consortium.

Activity 3: Who is the Censor?

The objective of this exercise is to consider who might be responsible for rating a website. Jot down on a piece of paper two or more groups that could possibly rate a website (e.g. a university website).

The Recreational Software Advisory Council (RSAC) is an Internet rating service (http://www.rsac.org/index.asp). Web developers can register with the service and, by answering some simple questions about their site, receive a PICS based rating of their site. Users can then set their browsers to block access to sites using the RSAC rating categories. This makes site selection more flexible.

Three things must be present for a rating based approach.

  1. Syntax for defining labels: This is the different aspects of the site to be measured. For example, a website could have labels describing the levels of Language, Nudity, Sex, and Violence.

  2. Syntax for labeling content: This is a rating classification itself for each of the labels. The each label's criteria have to be determined before giving its value.

  3. Method of retrieving labels. The labels, for example, could be embedded within the HTML file or kept as a separate file included into the HTML files when they are accessed.

Service Providers

Internet service providers can also enable censorship. They can, for instance, supply different user names and passwords to each family member, or to different management levels in a corporation. Each user is then given a corresponding level of "access authority".

The ISP can then run the appropriate software to block access to sites based on the user's access level. This can be based on block lists or site ratings.

Browsers and search engines

Some browsers and search engines directly allow for censorship. These may use a password system to allow for different levels of access. Some search engines allow for user feedback to provide information used to decide if a site should be removed from their index.

Social Methods

With so much of the emphasis of censorship placed on the individual — whether an employer, parent or website designers — to implement a censorship strategy, it is important that users are educated as to the implications of their actions. There is a moral responsibility associated with data access, and those who have the ability to control it need to be aware of the issues involved. Education plays an important role in raising awareness, and this has to be addressed from a global perspective.