Cleanfeed
From Seenoevil
CleanFeed is the name of an internet content blocking system developed by BT Group that uses the Internet Watch Foundation’s child abuse website database to prevent access to child pornography. To internet users accessing blocked websites through CleanFeed blocked pages appear not to exist.
Contents |
History
BT is one of the largest UK ISPs. In late 2003 with the support of the Internet Watch Foundation and the Home Office they planned an innovative blocking system, internally dubbed CleanFeed. Their intention was to prevent Internet customers from accessing any of the illegal images of children listed in the IWF database[1]. The existence of the system was leaked shortly before it became live in June 2004.[2]
Initial reports talked of teething problems where legitimate were blocked based on names in their URL (Legend Cmunications ISP status page reported problems with the cleanfeed proxy) Regardless of the authenticity of these claims any problems have apparently since been resolved.
In July 2004 [3] and then again in February 2006[4] BT published surprisingly high figures for users attempting to access sites blocked by CleanFeed. The exact nature of these figures has been criticized along with the operational secrecy that BT has relied on to support them[5][6]. In particular the increase in blocked traffic over time is more suggestive of access by automatic systems such as bots and crawlers as the IWF database increases in size than it is of an increase in people wishing to view these images, though the gradual addition of web pages containing images of 16 and 17 year olds to the IWF database (in line with the 2003 sexual offenders act) may have some effect as well.
Regulatory aspects
The Internet Watch Foundation’s child abuse website database was originally a project to enable ISPs to identify illegal content, and so fulfill their legal obligation to remove such content where possible. With CleanFeed it has developed into a way to block all such content at source. Conversations between the home office and ISP organizations have encouraged an expected 90% of internet access to be through CleanFeed or equivalent systems by the end of 2006 with a target of 100% by the end of 2007. According to Home Office Minister Vernon Croaker
"If it appears that we are not going to meet our target through co-operation, we will review the options for stopping UK residents accessing websites on the IWF list."[7]
The Home Office has also indicated the possibility of extending website blocking to articles that glorify terrorism within the meaning of the 2006 Terrorism Act. When asked about this issue Home Office officials have said:
"At present, the government does not propose to require UK ISPs to block content and our policy is to pursue a self-regulatory approach wherever possible. However, our legislation as drafted provides the flexibility to accommodate a change in Government policy should the need ever arise."[8]
While discussing the proposed law on extreme pornography on Radio 5 law sponsor MP Martin Slater mentioned the CleanFeed system as a means of blocking content proscribed by the proposed legislation on violent pornography. It was also previously mentioned in context of the proposed law in the House of Lords.[9] It remains to be seen whether the draft of the law will contain the flexibility to accommodate this.
Any extension of CleanFeed would require extension to the IWFs database and regulatory functions.
Implementation
BT, IWF and ISP organizations have been reticent about how CleanFeed operates. However enough information has become available to provide an outline of its operation.
CleanFeed is a two stage content blocking system. The first stage routes internet traffic based on IP address. If an IP address matches any abstracted from the IWF’s URL database it is passed through a web proxy, if not then it passes through transparently between website and user. In the second stage, traffic passed to the web proxy is checked against the exact details of the list of URLs on the IWF database. If it matches then the traffic is stopped and the customer receives a 404 ‘page not found error’ as if the page did not exist.
This hybrid system is a fast, cheap and apparently reliable implementation method. [10]
Criticisms
- CleanFeed puts censorship under the control of one central government mandated organization. In addition, the secrecy originally partly justified by the illegality of possession of child pornography protects the government from criticism as other content is blocked. Secret "blacklists" have no place in any open democratic country.
- Ultimately the IWF database constitutes censorship in the hands of the police. For a URL to be included on the database it only takes two IWF reviewers to agree. Website owners are not informed when their content is placed on the database and no one but approved partners has the right to access the database contents directly.[11] If website owners do manage to discover their content is blocked they can appeal to the IWF who in turn ask the police for the ultimate judgment on the legality of the image without reference to the judicial system [12].
- Cleanfeed could be used to aid people wishing to find such pictures. As well as it being conceivable that criminal website operators would be able to avoid being blocked by CleanFeed it’s also possible they could attack its operation directly. Of even more concern is the possibility that individuals might use CleanFeed as an 'oracle' to discover the location of websites on the IWF database, i.e. as a way to identify sources of child pornography. Richard Clayon of The University of Cambridge identifies one such successful method (Clayton, R (2005). "Failures in a Hybrid Content Blocking System". Workshop on Privacy Enhancing Technologies, Dubrovnik, Croatia.)
- It doesn't stop people looking at illegal pictures. Some have suggested that it only functionally prevents casual and accidental viewing of such material.[13]
