Censorship [was Re: Norwegian DNS compromized]

Nick Mathewson nickm at freehaven.net
Wed Feb 28 18:35:14 UTC 2007

On Wed, Feb 28, 2007 at 08:51:32AM -0800, Michael_google gmail_Gersten
> "He that would make his own liberty secure, must guard even his enemy
> from oppression".

There are many reasons why I do not think it is a good idea to add any
censorship code to Tor.  That's one of them.  Let me elaborate.

Let's assume for the sake of argument that some kinds of expression
are so totally pernicious and without merit that the world would be
better if nobody could engage in them.  (If you disagree, great, but
bear with me here.)  Even if this _were_ the case, would not follow
that it is a good thing to create censorship mechanisms for that data.

  - First, since censorship tech requires people to administer it,
    creating censorship tech places some people in control of what
    other people can say and see.  Even if the censors are enlightened
    minimalists who begin with the best of intentions, the risk is
    high that they will err, or be subverted, or be replaced.
    Centralizing authority like this creates a nasty point of failure,
    and a tempting target for attackers.

    (Before somebody proposes that a legal system be given the job of
    deciding what's okay, I'd point out that what's banned in France
    != what's banned in China != what's banned in the US[*] != what's
    banned in Russia != what's banned in Iran.  If you ban only the
    intersection of illegal things, you ban nothing.  If you ban the
    union of illegal things, you do the censors' job for them.)

  - Second, there's Paul's point above about legal ramifications under
    US law.

  - Third, censorship tech has unintended consequences.  Check out
    Richard Clayton's paper "Failures in a Hybrid Content Blocking
    System."  Clayton describes how BT, in an attempt to create a
    highly specific content blocking system, in effect wound up
    creating an index service for the very content they were trying to
    block.  This problem would only be _worse_ in a system like Tor
    where, if you wanted to block access to certain places, you would
    necessarily need to give exit nodes access to the blacklist.

Remember, it is possible to believe in right and wrong without
believing that moral judgments belong in the OSI stack.

Also, this should not need to be said, but debates about the merits of
Divine Command Theory[**] are not on-topic here.  Remember, just as
two wrongs don't make a right, an off-topic post is not sufficient to
make a reply on-topic.

[*] And don't get me started on obscenity law in the US: distributing
    "obscene" materials is generally illegal, but "obscenity" is
    defined in reference to prevailing community standards.  In
    general, there's no way to be quite sure whether something will be
    found obscene other than going to court over it, and there's no
    guarantee that what's found not to be obscene here will be found
    obscene 50 miles away.

[**] http://en.wikipedia.org/wiki/Divine_command_theory .  I've got
     strong opinions about _this_ too, but I also have the good sense,
     I hope, to keep my mouth shut about it on the mailing list. ;)

Nick Mathewson
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 652 bytes
Desc: not available
URL: <http://lists.torproject.org/pipermail/tor-talk/attachments/20070228/b9e79e81/attachment.pgp>

More information about the tor-talk mailing list