Charles Gimon gimonca at
Thu Dec 14 21:04:54 PST 1995

Forwarded message:
> From!owner-cypherpunks Thu Dec 14 17:36:57 1995
> Date: Thu, 14 Dec 1995 14:50:19 -0800 (PST)
> From: Sandy Sandfort <sandfort at>

> So far, no one has come up with anything stronger than specula-
> tion about my database question.  Some "anonymous" told me how
> easy it was to buy *phone numbers* on CD-ROMs.  Great, but I
> didn't give the guy my phone number.

It was probably a shrewd guess on the part of the phone peon,
combined with a fresh database from the telephone company. Are 
there many people in your zip code with the same last name as
yourself? If not, that pretty much answers your question right

When you pull a credit report from TRW's database, the only
information TRW needs is the first four (?) letters of the last
name, the initial of the first name, the numeric part of the
address, the first character of the street name, and the zip code.
I'll leave it to the experts in information theory to explain
that in rigorous technical detail.

Given only a last name and a zip code, I wouldn't be surprised
if you found the proper individual most of the time. (If you're in
Minnesota and you're looking for Swenson in 55419, you may need
more info, but not much.)

Another anecdote to add to the pile: I moved to a new apartment
last May. For various reasons, I got an unlisted number, and had
my credit card bills and magazine subscriptions sent to a mail
drop (MBE). The phone, gas, electric and cable bills went to the
new apartment, not to the mail drop.

I didn't get any junk mail at the new apartment until a couple
of weeks ago--right after I changed my subscription to Byte to
come here (now I'm getting AOL disks, etc.). Before that, I got
no junk mail here (except from the phone or cable company). I
get almost no telemarketing calls; I used to get at least one a
night with a listed phone number.

My experience appears to be that credit card and magazine companies
sell lists; utility and cable companies don't. Mass mailers must
not get unlisted number customers on the lists they get from the
phone company. Again, this is only from my experience, all disclaimers

And all this has no relevance whatsoever when you bring the 
government into the picture.

Crypto relevance? Well, I did mention information theory...

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