Re: third-party datestamp site?

David G. Durand (
Wed, 17 Mar 1999 08:57:22 -0500

At 8:21 AM -0500 3/17/99, James Tauber wrote:
>Here's an idea for a site:
>You submit a document and it returns a date-dependent digital signature for
>the document for a small fee.
>Another party can submit your document with the date it was supposed to have
>been submitted on and the site verifies it.
>Third-party date stamping over the web. Does such a beast currently exist?
>Or is this stupid?

My wife's friend Stuart haber is co-inventor of the standard way to do this
(cryptographically chained timestamped hash codes). There are a few URLs of
citations, etc. And they did start a company (Surety), to commercialize the
technology. I don't know healthy the business is.

I stuck in one of the many other sites offering some variation of this service.

The thing I like about Stuart's service is that there's a need to have a
public "hash code of record," every so often so that clients and courts
don't have to depend on trusting the hash authotirty. They use dead-tree
broadcast replication of identical bits: by publishing a classified ad in
the NYT every day -- thus leaving a tough-to-falsify audit trail of
sufficient permanence for commercial transactions.

-- David
David Durand \
Boston University Computer Science \ Sr. Analyst \ Dynamic Diagrams
MAPA: mapping for the WWW \__________________________