Wednesday, December 31, 2008

A different level of impact

Loose thoughts by Bjorn Landfeldt

After the government released its report on Internet content filtering senator Conroy released a statement that the government will test P2P filtering as such tools currently exist. This is very interesting because the bar is raised considerably if this is the case.

In the report I did not raise and strong concerns with performance degradation at the ISP level when comparing HTTP requests to a blacklist. I believe the performance penalty can be significantly reduced by purchasing additional equipment and the ISPs can be compensated for such roll out. The current trials can actually answer some of the questions as to the performance penalty and cost to alleviate them in terms of additional equipment purchases.

However, with P2P filtering the situation is very different. In this case, the filtering system has to do deep packet inspection to figure out if something should be banned or not and this is very different to checking terminating address. The deep packet inspection will be used to try to identify what kind of content is accessed since in a P2P content distribution network end addresses are useless. This puts us in the realm of dynamic filtering which pretty much is the worst nightmare for the Australian ISP industry and necessarily will mean significant performance penalties for the Australian public. Even if some video in a bit torrent would be called "child abuse that is illegal in Australia and should be filtered by the government" a filter would have to perform analysis of this text to determine if the media should be filtered. Changing the name of this file to "daisies in summer" and the filtering system would have to analyse the content of the video itself to determine if it is illegal and should be blocked.

In addition to performance penalties, such system raises much stronger privacy concerns. Even if very little content would actually be blocked with such system, someone is really checking how Australian citizens are using their network connections.

It will be interesting to see how this will pan out.

Thursday, December 25, 2008

It is a shame

Loose thoughts by Bjorn Landfeldt

Over the past couple of days there has been lots of articles and blog posts about Internet content filtering in Australia. Sine I am involved in this debate I have spent quite some time to go through the posts to see what interesting thoughts and views are out there.

I am a bit surprised at the emotional charge this issue has and really think it is a shame that the public debate is overshadowed by a sea of emotional outbursts and wild accusations. Especially, I think it is a shame that Senator Conroy's blog is flooded with such content, that is where people should try to be taken seriously.

I think it is absurd to compare the Rudd government with the Iranian or Chinese governments. I am also surprised that senator Conroy actually bothered to meat that criticism.

I am equally amazed at the notion that if you appose this scheme in any way you support child molestation.

It is becoming clear to me why this issue became such a prominent political issue in the latest election campaign and why it is so important to win political ground. It is a shame.

I am a proud Australian since 2007 but I was born and raised in Sweden. For all the lobby groups that are seriously concerned with children's welfare, I urge you to have a look at a country that is running at a few parsec higher speed than we currently are. I live in Sydney's South-West, in a suburb that had a plane crash, two shootings and a siege resulting in 4 dead all during last week. There is a lot of child neglect and abuse going on out here and this is something to really get upset about.

Of course, really caring for our children means a hefty tax bill......

Nothing is that easy, it is a shame.

Tuesday, December 23, 2008

Internet content filtering

Loose thoughts by Bjorn Landfeldt

There was an article in the Sydney Morning Herald this morning regarding a report I was involved in preparing for the Australian government late last year. The study was concerned with the feasibility of filtering content on the WWW at the ISP level. My own contribution to the report was not the major part and I mainly carried out a limited technical study

I feel that it is necessary to make a few things a bit more clear concerning the news paper article.

First, I don't think the study was very secret. In fact, the study made a wide consultation with the Australian ISP industry, content providers and other organisations / stake holders. There has been wide spread knowledge of this study even though the findings have not yet been widely released as far as I understand after reading the article. It is not my place to comment on at which time the government releases its reports even though I see no real reason not to release this specific report.

The issues raised in the report have largely been covered in preceding reports, at least the sections I was providing input to and even though they are very important issues to consider, I don't think they are damning since the issues are well known.

My stand on this issue is that there is a need to increase the scale of investigations if any such scheme should be made mandatory. If such a scheme is voluntary many of the difficult issues become obsolete or at least manageable. The following opinion merely reflects publicly available information that is not limited to the report. Anyone can search for this information in their local library or on the world wide web.

So, what is the big issue as I see it? A blacklist requires manual effort in order to determine what should be included. The Internet is a network of networked computers that carry information in many forms and realms, one of which is the World Wide Web. If we restrict ourselves to talk about only WWW, we have a global network with billions of pages worth of information. The information is made up of all different languages of the world and incredible diverse. Some information has a very high profile and some information has very limited visibility. Since a blacklist would rely on user reporting, it is questionable how efficient it would be to locate unwanted content in the first place. Second, every case would have to be tried to see if it breaches Australian law and falls within the categories specified for the filtering list. It will be a very difficult task to do this for content in the grey zone in all different languages. If the point is to stop child pornography, determining if a model is 19 or 25 in content from a different country with different jurisdiction is not an easy task and would be quite labour intensive. The next question is who is responsible for blocking of material that is legal if the wrong judgement is made?

The only way to identify such material quickly and significantly limit the risk of accidental access is to do some form of dynamic content filtering. However, the state of the art of such technologies is very limited in accuracy and if they are to be used there is a consequential performance impact on the response times of systems or at least an increased cost for the service provider. Current filters are rather good at detecting certain patterns of information such as a combination of many images and certain keywords usually means a porn site. However, there are at least two additional dimensions to consider. First, the current filters only look at such patterns, they do not try to analyse the actual content in any meaningful way. It is therefore difficult to distinguish between different types of content where there are similarities. For example, if a web site contains information about sex education or erotic content. Second, more and more content moves to other forms of multimedia and filtering and detecting the nature of content is much much harder in this case. For example, analysing a video and detecting that it has adult content is not a lightweight computational task. Separating sex education from porn is even harder. Third, if indeed there would be widespread filtering of content the providers would see a need to obfuscate content to fool filters. When we step into this realm it becomes very difficult for any filters to keep up.

This discussion can then be applied to an environment with other addressing realms than the WWW such as P2P networks and social networking applications and realms which shows that the level of difficulty is very high indeed. There is also a strong movement to anonymise users on the Internet to counteract information logging. Using simple tools such as VPNs to cross the Australian border would also enable circumvention of any centralised filtering scheme.

I believe it is a shame that the issue became a political issue in the latest election campaign. The question of protecting us from certain content is important and there should be a healthy and public debate about it. I have no knowledge of what other steps the government is currently taking to investigate this matter but I hope the scope of investigation is much broader than only doing a performance study of blacklist filtering.

I tried to download one of the free netalert filters for the computer my oldest daughter is using a while ago but the provider web site seems to be down. It is a shame, because I don't want her to see many things out there at her age, but I am making that choice and I accept responsibility for the over blocking.

Bjorn Landfeldt