another service

[pmetzger@shearson.com (Perry E. Metzger)]

>From: tcmay@netcom.com (Timothy C. May)

>Eric Hollander writes:

>> I have thought of another service, like the depository, which might be
>> useful to the user community:  a time stamping notary service.  This would
>> have less security problems than the depository and would also be neccessary
>> if RSA'ed documents are to replace contracts and other paper documents used
>> in business.

>Bellcore is offering some form of this service, or plans to. Stuart
>Haber, one of the codevelopers, described this at last year's Hackers
>Conference and presented a paper at the Crypto '90 conference, or
>possibly the Crypto '91. (I have a Xerox of the paper someplace and
>may be able to dig it up if you're interested)

Haber isn't offering quite the service described -- he worked out a
much nicer notarization and time stamping protocol thats really neat.
Every day or two a critical number spat out from the service gets
published in the classifieds of the New York Times so people can
independantly verify that there is no cheating. By the way,
technically, the service doesn't do timestamping, just a verified
ordering of notarized documents. Unfortunately, there is no
mathematically provable way to know what time it is -- you must trust
someone on that.

Stu's a really nice guy -- maybe someone should encourage him to join
this list.

Perry