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Kumar Parakala | October 20, 2009

The release last week of the ACS report on ISP filtering has reignited the debate about internet censorship, with the ACS e-security task force suggesting that, if mandatory internet filtering is to occur, then a multi-faceted strategy would be needed to ensure that children are protected from dangerous or inappropriate material online.

The ACS neither supports nor condemns internet censorship, but given the current government policy to introduce mandatory ISP filtering, we established the e-security task force late last year to examine the technical issues associated with this approach in an objective and balanced way.

The task force, which includes some of the nation’s leading e-security experts, suggests that if the government remains committed to this policy, then ISP-based filtering, while an important first step, will not be sufficient to achieve the desired result.

Filtering alone is unlikely to adequately address cyber security issues or significantly impact those who deliberately produce, distribute or search for illegal material, since there are too many technical loopholes that can be exploited to evade detection.

With the government seeking to deliver on its election commitment to require ISPs to offer a clean feed internet service to all homes, schools and public internet points accessible by children, it’s clear that a mix of technical and education-based initiatives will be needed.

According to the ACS report, the diversity and sheer volume of content and web sites on the internet, the determination of those generating malicious or illegal content and the need to balance e-security concerns with freedom of speech and censorship issues means that there is no one solution that will solve all filtering needs.

While acknowledging the value of filtering, the task force has also called for better education of both parents and children on using the internet, and greater transparency around blacklists and their criteria.

The issue of internet filtering has been a contentious one with many stakeholders protesting that any moves to require ISPs to introduce filtering will degrade network performance and increase costs to consumers.

Certainly these are valid concerns and the task force report provides substantial detail around the technical issues associated with the different types and levels of filtering.

Some of the challenges identified include:

• A lack of clear definition about the types of content that will be subject to filtering;
• The technical limitations of automated ways to analyse video, pictorial and audio content;
• The need for clear and consistent criteria behind content labelling and rating systems;
• The impact on network performance of content filters, depending on where they are placed within the network architecture;
• The need for consistency in the blocking of content and how to avoid overblocking or underblocking;
• The difficulty in maintaining up-to-date black lists, white lists, keywords and phrases because of the rapid rate at which new internet content is being generated;
• How to effectively manage user-generated material, which is created on the fly since it is practically impossible to accurately label or rate these sites and content; and
• The need for ways to deal with encrypted traffic and secure channels, as encryption impedes filtering.

The report called for the government to clearly define the objectives of any ISP filtering program and provide more information around desired performance standards, the type of material to be filtered, reporting processes and the type of traffic and filtering mechanisms to be used.

Task force spokesman and Director of Information and Networked Systems Security Research at Macquarie University, Professor Vijay Varadharajan, said we need to clearly understand what we are filtering and why, as well as having specific strategies for how this might best be achieved.

Different levels of filtering will act with varying levels of efficiency and have different impacts on performance. There are obvious technical issues relating to the filtering of certain types of content, such as SSL content, peer-to-peer traffic, internet chat rooms and instant messaging from social networking sites.

Many of these are popular ways for seasoned purveyors of illegal material to communicate and exchange files, he explained.

The six experts on the task force believe there is no single mechanism that can accurately filter out or block illegal material on the internet 100 per cent of the time. A successful approach would need to incorporate filtering technologies at the ISP, user and enterprise level, as well as increased professionalism and tighter controls around domain name registration, education at all levels of society and greater oversight by parents.

The growing importance of the internet at all levels of society makes it essential that we seek ways to protect users and promote greater confidence in the internet as a safe and effective platform for business, education and social interaction.

We look forward to working with the government to identify effective strategies and tools that will deliver the right level of protection without compromising performance or negatively impacting ISPs and other ICT businesses.

Kumar Parakala is chairman of the ACS. www.acs.org.au