semi-public data?? (Re: phone lookups)

[Jeremy Barker]

Peter Fairbrother wrote:

> Adam Back wrote:
>
> > I think a more pertinent question is:
> >
> > - is the information public or not?
> >
> > if it's public it's public -- no semi-public, or public but only to
> > people who pay 200 pounds, or public to people who show up at an
> > office.
>
> There is an unmentioned difference here, brought about partly by the
> development of computer search programs, although the distinction existed
> before. Information is useless unless it is *looked at.
>
> Anyone can look up someone's number in a telephone directory, from knowing
> who that someone is, but it is illegal in the UK to look up the someone from
> a number.

That is plain wrong.  There is no legal reason why you should not do a reverse
lookup.  The only reason there is no published reverse telephone directory in
the UK is because BT chose for policy reasons not to provide such a directory.
Some people need to do reverse lookups and in the days when the directory was
only on paper did so with considerable time and expense.  For some reason that
policy decision is perceived by some as a legal restriction but I examined the
question several years ago and found there was no reason to think it had legal
backing.

There are some legal problems about computer-based reverse lookups, but again
there seems to be nothing in principle (at least with the old data protection
law) to make doing them illegal.  The major legal problems concern copyright and
have become worse with the advent of the database right.


> In terms of a forward lookup a listing in the phone book is public. In terms
> of reverse lookup it isn't public (at least in law and public perception,
> although in practice it is).

The whole of the data in the published telephone directory is in the public
domain and there is no legal reason why people should not use it in whatever way
they see fit.  For example, one of my friends is one of a very small number of
people with a particular surname in the telephone directory.  I once had the
wrong house number in my address book so had to look in the directory at a local
shop to find the correct one - a quite proper and legal use of the data in the
directory.


> [I could** devise a cryptographic solution to implement the one-way nature
> of the public perception of telephone directory lookups, but unfortunately
> at a cost that would be enormous, involving a change to the way the phone
> number system works. This won't happen in real life.]
>
> -- Peter Fairbrother
>
> *[OT] trees falling, forests, nobody there, sound, does it exist? It does if
> you _might_ look, c/f Elitzur-Vaedman Bomb Testing (!).
>
> **[OT] But there is the question; do one-way functions exist?

jb