Politech: FC: Australian government publishes censorware effectiveness report

[Declan McCullagh <declan () well com>]

---

Date: Tue, 26 Mar 2002 13:08:08 +1100
From: Nathan Cochrane <ncochrane () theage fairfax com au>
Organization: The Age newspaper
To: Dave Farber <dave () farber net>, Declan McCullagh <declan () well com>
Subject: Australian Government releases content filtering survey in time 
for Philadelphia trial
Hi Dave, Declan

Call it kismet, providence or good timing, but the Australian Government 
has released a 90 page report into the effectiveness of censorware as the 
CIPA goes to trial in Philadelphia.
http://www.interesting-people.org/archives/interesting-people/200203/msg00184.html
http://www.politechbot.com/p-03297.html

The report was commissioned by the Australian Broadcasting Authority 
(www.aba.gov.au), which is responsible for censoring the Internet in this 
country, and conducted by the Commonwealth Scientific and Industrial 
Research Organisation (www.csiro.gov.au).
http://www.aba.gov.au/internet/research/filtereffectiveness.pdf

"Effectiveness of Internet Filtering Software Products" gives a basic 
background to the problems of censoring Internet content. It then addresses 
the different approaches vendors use, such as inclusion/exclusion, content, 
source and image filtering. It finishes by reviewing 14 products and 
services including Cyber Patrol 5.0, AOL Parental Control 6.0 and Net Nanny 
4.0.
The report doesn't take a moral or ethical stance, but outlines what can be 
achieved with the technology available.
Some highlights from the report:

"While it is technically feasible to block access to all undesirable 
Internet content, no Internet blocking or filtering scheme will ever be 
100% effective, or resist a determined and informed attacker, but many of 
them will be perfectly adequate in normal use."
"A completely safe Internet may well be a very restricted Internet, 
especially when new types of content and new distribution technologies emerge."
"Many filtering products are based on lists of Web sites that are supplied 
by their vendor. These lists are expensive to produce, as they have to be 
compiled by having people examine and classify Internet content, and as a 
result these lists are often closely held proprietary information. The 
secret nature of these lists can make it difficult to know just what 
content is being blocked and for what purpose.
"These lists also reflect the values of the organisations and people who 
compile them, and may not reflect the values of Australian society as a 
whole. Some Internet activists (Peacefire) complain that commercial 
filtering products reflect US-based conservative and religious values, and 
as such may not reflect the more liberal values held by Australian society. 
Cultures differ considerably in their concepts of acceptable
content and filtering products really have to customise their lists to meet 
local cultural norms."
"Content filtering is a difficult problem. Even text-based filtering 
requires some ability to determine context (and meaning) for words they 
discover. Early products were infamous for simplistic filtering, with the 
blocking of "breast" cancer content being the most quoted example. 
Filtering products have improved since those early days but the task is 
still very difficult and moderately high error rates can be expected. 
Filtering out non-textual information, such as photographs or video, is 
much more difficult and problematic."
"All filtering technologies are fallible, and the more effective they are, 
the more they risk intruding on general Internet usage. Products have to 
strike a balance between filtering out undesirable content, and allowing 
access to (possibly unknown) useful content. The white list products are 
the most effective because they are the most restrictive and constrain 
users to a very small part of the Internet."
"Much attention is paid to filtering Web pages but undesirable content can 
be found in many places on the Internet, including newsgroups and file 
servers. Some of the more tightly filtered Internet services, such as some 
of those designed for the educational market, resolve this problem by 
completely blocking access to all Internet services other than the Web and 
e-mail. This approach is certainly safe, but would be unacceptable for the 
general Australian community and so these other sources may have to be 
filtered as well."
"An emerging problem with filtering Web traffic through the use of 
server-side filters is the rapidly increasing use of the Web's protocol 
(HTTP) and port (80) for other purposes, such as e-commerce and Web 
Services. Filtering all HTTP traffic could result in degraded performance 
for major applications, rather than just slowing down
interactive Web browsing."



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