Shostack + Friends Blog Archive


Blind Signature Patent Expiration Party

we-accept-ecash.jpgFriends, colleagues, and co-conspirators,

It has been 17 long years and now the time is finally here to celebrate at


A party to celebrate the expiration of the Blind Signature patent.

U.S. Patent 4,759,063 (“Blind Signature Systems“) to David Chaum is the core
invention enabling privacy-protecting electronic payment systems and
credentials. It was a truly ingenious, ground-breaking contribution.
Unfortunately the existence of the corresponding patent, which was
notoriously difficult to license, prevented this great invention from
receiving the wide use that it so very much deserved. For a copy of the
patent, see

Unlike copyrights these days, patents do expire. The blind signature patent
will expire on July 19, 2005, next Tuesday. Since weekends tend to fit
better with the schedules of potential party goers than weekdays, we are
holding the party this Saturday instead.

The 17 years that this patent has been in effect has been an awfully long
time for the many of us that hoped to make use of this technology to help
citizens to maintain privacy in the age of the Internet and the patent’s
expiration is a much overdue reason for celebration.

If you know what blind signatures are you are invited.

This Saturday, July 16, starting at 1:00 PM PDT

Since the number of inquiries I received in response to the party
pre-announcement exceed the maximum occupancy limit of my home and since the
weather promises to be excellent, we will hold the party in a beer garden
instead. Drinks are on me!

We will meet at the
Alpine Inn (aka Alpine Beer Garden)
3915 Alpine Road, Portola Valley, CA 94028 USA

Those that can demonstrate that they have created a full system that makes
significant use of the blind signature patent by 4 PM on Saturday will be
invited to and receive a free dinner at the afterparty. So get coding!
(Pr0duct Cypher, where are you)? A team of judges will determine if a
particular system qualifies for the award.

A handful of us plan to have dinner at a swanky restaurant on patent-free
Tuesday. Email me or talk with me at the party if you are interested in
joining. Space is limited. You will have to pay for your own food at the
Tuesday dinner unless you qualify for the award above or your name is on the
blind signature patent.

Looking forward to see you all this Saturday,

2 comments on "Blind Signature Patent Expiration Party"

Comments are closed.