Abstract
The internet was founded on the philosophy of openness and its inventors hoped to provide a means through which information could be shared freely among participants. However, it has grown to become a heavily restricted medium with some form of censorship being implemented everywhere and severe censorship in a few places.
This paper highlights the reasons why censorship is on the increase. A list of the technologies employed to achieve censorship is given followed by the techniques used. The paper concludes by observing that internet censorship will continue to increase in coming years as governments, organizations, and parents seek more control in the internet.
Introduction
The Internet has emerged as the most important invention of the 21st century. This creation has acquired the status of “most important technology” due to the positive impact that it has had worldwide. However, the internet also has some negative impacts and this has led many people to regard the technology as a double-edged sword with both negative and positive attributes.
On the positive, it has made communication easier and turned the world into a global village through its interconnectivity ability. It has increased the ease with which people all over the world can access valuable news and information. On the negative, the internet has increased the security threats to all people by making it easy for terrorists and anarchists to access dangerous information such as how to make bombs.
Objectionable and inciting material is also easily available and this might threaten the stability of the society. Governments and organizations have therefore been forced to take steps to mitigate the potential harmful effects of the internet. The motivation behind these actions has been to enable people to benefit from the wealth of information contained in the internet while at the same time safeguarding the lives of innocent people.
Software solutions have been used to prevent access to any material considered dangerous or objectionable. While some people see censoring as a positive act that protects the society, others view it as a violation of the individual’s right to access information freely.
Censorship Mechanism
Internet filtering or censoring refers to the act of restricting access by internet users to material that is considered dangerous or in some way offensive. Censoring is achieved though filters and firewalls which are configured to prevent access to certain material or prevent the publishing of certain content.
Censorship in the internet can also occur in the traditional sense of the word where material is removed from the internet to prevent public access. In addition to universal censorship, material can also be restricted to particular audiences based on attributes such as user age or occupation.
Many governments have censorship policies in place to help control access. However, effective censorship is yet to be achieved since the internet is rapidly growing and changing. Different devices and networks are occurring and technologies such as social networking are changing the manner in which people access the internet.
Internet filtering is conducted on a number of unique levels. The most pervasive filtering occurs at the Government level. The Information and communications ministry of the respective country does this filtering.
The state dictates the kind of websites that its citizenry can have access to and deny access to websites that are deemed dangerous or objectionable. Countries such as Saudi Arabia, China, Iran, and Syria regularly engage in this government level blocking. The governments cite security concerns and decency violations as the major reasons for preventing their citizens from accessing numerous sites.
Another level of blocking is the Internet Service Provider’s (ISP) level. ISPs typically provide filtering and blocking services to their clients either on client request or universally. The ISPs that provide universal filtering usually do this at the suggestion of governmental agencies in the country. Kuwait, Singapore, and Malaysia ISPs provide filtering and blocking services at the request of the government.
ISPs in some countries such as the US and most European countries let their clients chose if they want filtered or unfiltered internet services. However, most ISPs prevent their users from using legitimate privacy and anonymizing tools since such tools will render filtering systems useless and enable the user to access censored material.
Filtering can also take place at the Organizational level where individual organizations enforce some form of internet filtering on their LANs and intranets. Organizations such as banks, schools, and hospitals conduct internet filtering for reasons such as increasing worker productivity and preventing access to inappropriate material.
For example, filtering ensures that workers do not make use of the internet for leisure surfing or chatting during work hours. The final level of filtering is the Parent’s level and individual parents implement this level.
This level of filtering is necessitated by the lack of trust by parents on the ability of the government or ISPs to filter out all the information they consider inappropriate for their children. Parents therefore use commercially available filtering software to further restrict access to the internet by their children.
Censoring Technologies
Censorship implementations have acquired a wide market as the need for censoring by governments, organizations, and parents increases. Censorship techniques can be categorized as hardware based and software based. For filtering and blocking internet content, software based technologies are employed.
Hardware based technologies on the other hand are used to classify network traffic and perform inspection on packet headers in order to deduce the content of the traffic.
As of yet, the perfect Internet censor software has not been developed and the censorship software used experience some errors. Even so, the censor software in today’s marketplace is able to meet majority of the needs of the government sector, organizations, and parents. There are three components to internet censorship and this are: social, political, and technical.
These components sometimes interact with each other and they can be used concurrently for higher effectiveness. For example, authoritarian regimes use highly advance technologies, social conformity though the threat of harsh punishment and political philosophy to foster acceptance of the imposed censors by the population.
These three components must be dealt with in order to counter internet censorship. Anti-censorship proponents must deal with the technological, social, and political structures in order to defeat internet censorship.
The filtering and blocking process is hidden from the public and people are not made aware of what type of content is blocked. Because of this, filtering technologies are susceptible to the problem of over-blocking or under-blocking.
In over blocking, the filtering technology employed blocks out content that it is not configured to allow the user to access. In under blocking, the filtering mechanism fails to block out material that is supposed to be filter out.
Internet Censorship Trends
The worldwide growth in internet access and usage has been accompanied by a steady rise in internet censorship. While there has been a steady increase in internet censorship since 1993, the most dramatic increment was observed between 2007 and 2010.
Government level censorship has been the most significant with authoritarian regimes such as China, Cuba, and North Korea conducting the most pervasive internet censorships.
China has established herself as the country with the most sophisticated internet censoring technology. Other authoritarian governments have therefore tried to implement the methods and policies used by the Chinese in their attempt at controlling access to information on the internet in their countries.
However, authoritarian countries are not the only ones engage in internet censorship. The world’s leading champion of democracy, the United States, also engages in this activity. The government is allowed by the Supreme Court to censor certain material that is not protected by the First Amendment.
This includes material that is meant to incite lawlessness, defamatory material, and obscenities such as child pornography. The government is also authorized to keep material that it deems important for national security secret.
In the Middle East countries, most of the blocking and filtering is done on political, cultural and religious considerations. The religious considerations are included since most of the countries in the region have Islam as the predominant religion.
To implement this censorship, most of the ISPs in the region make use of commercially available filtering software mostly obtained from the US. Secure Computing and Websense, which is a US company, provides most of the filtering solutions used by the Middle East ISPs.
Considering the prevalence of internet filtering, a number of studies have been undertaken to help quantify the instances of censorship. Dievert et al have engaged in the most insightful study on global internet filtering. In another related study, users are allowed to report allegedly blocked websites and this user-generated data is used to come up with a database indicating which sites are blocked and by which countries.
Filtering Techniques
The filtering tools employed make use of a number of techniques to carry out the blocking.
TCP/IP Header Filtering
This is the most common filtering technique and it is also known as blunt filtering since it blocks out entire sites based on their IP address. The IP (Internet Protocol) is a basic protocol used by all communicating devices to direct their traffic across the internet. The TCP/IP Header filtering examines the sender and recipient information contained in an IP packet.
IT then blocks out all packets from an IP address that is known to contain objectionable material. A major advantage of this technique is that it is cheap and simple to implement since one only needs to highlight the IP addresses that need to be blocked out.
However, this method suffers from a significant disadvantage since it leads to over-blocking when a single IP address that contains useful and valuable content is blocked out since it also hosts a site with objectionable content.
TCP/IP Content Filtering
This technique is also called the Deep Packet Inspection (DPI) and as the name suggests, it involves inspection of the packet more thoroughly than simply inspecting the packet header. As such, the approach does not block out entire web addresses or web sites, instead, individual pages that contain the objectionable material can be removed.
This approach avoids the problem of over blocking since only packets that contain prohibited keywords are filtered out while the rest are displayed to the user. However, this method requires specialized hardware, which makes it hard and costly to implement. Significant computation power is also required to inspect all the data packets which makes the computational cost of this method very high.
DNS hijacking Filtering
Domain Name System hijacking allows the ISP to implement filtering by blocking out the name of a site. As opposed to filtering an entire IP address, this method allows a targeted website to be blocked. The ISP relies on a list of blacklisted domain names mostly provided by the government to implement this filtering. The ISP then configures its DNS server to refuse requests for those domains by the user.
A major demerit of this method is that it can be bypassed easily by someone with technical knowhow. In addition to this, blocking out entire domains restricts access to pages within those domains that might have valuable information that is not objectionable.
More sophisticated implementations of DNS hijacking filtering (that make use of keywords or URL filtering) are being implemented to address this problem and therefore increase the accuracy of this filtering technique.
Keyword Filtering
This method blocks access to websites based on the presence of banned words in the URL. The method also blocks search engine searches that contain certain blacklisted words. Many countries are using this technique more frequently due to the blocking power that it presents. Due to the processing power required, it is the most expensive technique to implement.
HTTP Proxy Filtering
This method makes use of the web proxies that are used to reduce bandwidth requirements and therefore improve performance. This is achieved by storing copies of recently downloaded HTTP content so that any future request for the same content do not result in the web server responding with the same content repeatedly.
By using the filtering proxy, requested destined for or coming from banned sites are prevented from reaching the caching proxy. This provides a thorough filtering comparable to the TCP/IP content filtering without compromising the efficiency of the network.
Other Approaches
In addition to the mentioned methods of blocking and filtering, other means can be used to regulate web content. Governments can ask that entire websites be removed therefore making the content of the site inaccessible to all.
The state can also tamper with the connectivity to a particular website making it too slow therefore dissuading users from visiting the website. Such methods might be used in conjunction with the software tools filtering to achieve the desired censorship.
Blocking and Filtering Tools
Bess
Bess is a filtering tool that was created by N2H2 and later acquired by the Secure Computing Company which merged the tool with another one of its filtering tools, the SmartFilter. The tool is available commercially as SmartFilter, Bess Edition with a target market of schools. The tool uses sophisticated technology and human review to reduce the errors that general keyword blocking methods cause.
The tool makes use of human reviews to allow access to sites with material on breast cancer and sex education. Such sites would be blocked out by most tools that use “keyword blocking” due to the presence of the word “sex” and “breast”.
Bess had 38 blocking categories (as of 2006) and its elaborate blocking allows access to websites that might have educational value but contain pages that have content that is unsuitable for children. However, the tool has engaged in pervasive blocking by filtering out some websites that are against censorship as well as websites that report on filtering software.
ClickSafe
This filtering tool makes use of content-based filtering and it relies on keywords and graphic recognition to filter out objectionable material. The tool is especially efficient in filtering out pornographic content and it is able to accurately differentiate appropriate from inappropriate content even if key words such as “sex” or “breast” are used in both instances.
For increased security, the list of prohibited sites is made invisible and the user does not know of these sites. However, users are allowed to check if a website is included in the prohibited list by keying in the full address to the site. In addition to the objectionable content blocked out, the company also blocks out sites that have information or programs that can be used to compromise blocking software.
The accuracy level of ClickSafe is impressive with the tool being able to block pornographic sites 90% of the time. Instances of over-blocking (where “good sites”) are blocked out stands at only 5-10%.
Conclusion
The internet is turning into a heavily regulated sphere and internet censorship can only be expected to increase with coming years. This paper has reviewed the censorship mechanism used and proceeded to highlight the technologies employed to achieve censorship.
The filtering techniques used and their merits and demerits have been discussed. Filtering and blocking tools will continue to experience high use as the internet becomes even more controlled in the future.