Kehoe Letter

[list account]

My letter to Louise Kehoe as planned:


Louise Kehoe <Louise@FT.com>,

I read your recent article on encryption and law enforcement.
It was a relatively good article, and I was pleased to see a
serious newspaper covering the subject.

Unfortunately I got the impression you were slightly too swayed by 
the arguments of one particular community.  The truth is that privacy
and law enforcement goals are not in conflict.  Just as locks and law
enforcement goals are not.

The arguments from some government quarters that cryptography must be
restricted to that which allows government accesss are based on these
fallacies:

1)  Widespread crypto will make lawful data access impossible.

    In fact data access is not always prevented by cryptography.
    Ross Anderson's paper "Why Cryptosystems Fail" (a recommended read)
    (http://www.cl.cam.ac.uk/users/rja14)
    shows that there is plenty of scope for traditional police data access
    by bypassing any cryptography completely.  This could mean concealed
    microphones recording plaintext voices even if an encrypting phone is used.
    Likewise recording devices hidden in keyboards to capture passwords.
    And as for material on seized disk drives, there are various possibilites
    for reading encrypted or deleted data besides simply insisting in court
    that a suspect provide the plaintext.  Also some of the most helpful 
    clues the police might look for come from "traffic analysis" - noticing
    who communicates with whom and when - regardless of message content.
    And crime involving the real world can be seen in the real world - after
    all the plotting, if I commit a crime I can be caught at the scene or
    from the resulting investigation.


2)  Law enforcement access will be only according to court approval.

    If the true intention was to support approved access then arranging it
    as in (1) above would suffice.  Clearly there is concern that fishing
    expeditions (skimming a large amount of non-suspect traffic) will
    be impracticable.  And so they should outside of a police state.

3)  We have a budget to angle for, so prevention is worse than cure.

    Cryptography is a defensive technology like locks.  It could have
    prevented billions of pounds in mobile phone fraud if employed in
    a kerberos-like manner to prevent cloning.  It can be an important
    part of computer defences against intruders and in itself has no
    capacity to harm at all.

4)  Criminals will use it in the manner intended.

    For a LEAK (law enforcement access to keys) scheme to be of
    any use the criminals must use it and commit their plans to it.
    Even if the scheme is made mandatory this sounds unlikely to many
    people.  Even if they do use the scheme there are ways to defeat
    the LEAK such as superencryption (encrypting with an unauthorised
    scheme first).  Some forms of superencryption can be disguised as
    legitiate traffic so that even when intercepted the message is not
    incriminating.
    

The FBI and others have decided to debate the subject on ground that they
have no right to.  I'm fed up of people pretending that any opposition to
a police state amounts to support for terrorists, child molesters, drug
dealers and money launderers.  

The only industry support for restrictions comes from companies that hope
to sell governments the "solutions" they are considering, or from companies
bullied by new rules into starting certain projects.

You might want to visit my website.  Please let me know if I can be of
further help.  

I enclose details of a mailing list you might wish to join.
To join send "subscribe ukcrypto" in the body of an email to
Majordomo@maillist.ox.ac.uk

 [list details snipped]

--
##############################################################
# Antonomasia   ant@notatla.demon.co.uk                      #
# See http://www.notatla.demon.co.uk/                        #
##############################################################