Subject: [saag] Harber and Stornetta Expiry

From: Phillip Hallam-Baker <[email-masked]>
Date: Wed, 13 Jul 2011 16:44:10 -0400

Is anyone interested in getting together to discuss possibilities for IETF
activities in the wake of the expiry (in at least some jurisdictions) of the
above patent?

Harber and Stornatta is the chained digest patent that provides a means of
proving that a document was digested after date X and before date Y. In
brief each has is chained into the next and the result periodically
published in the classified section of the NYT. This allows a proof that the
digest was performed in the interval between two successive hashes.

The reason this is of immediate practical interest is the problem of
'unhistory'. As a lot of the primary collection and storage mechanisms for
historical data become digital there is more and more scope for falsifying
them.

With an ordinary time stamp authority the question 'can we trust Alice not
to modify the document' becomes 'can we trust the TSA not to collude with
Alice'. There is an improvement but it is still a thin chain of trust. I
would like to see the task of falsification be made much harder.

When only one TSA had the technology there was no particular advantage to
using it over a regular notary service either. The NYT will probably stop
being printed in a few years time, libraries will certainly stop keeping
paper copies (many have already) so the claim of permanency is being
undermined in any case. Now there is an opportunity to do something more
interesting.

The technology is one thing, but to make it useful we need a social
infrastructure to support it. The value of this approach above and beyond an
ordinary TSA comes from having hundreds of independent agencies all
providing services and auditing/hashing each other.

So imagine a situation where there is a 'tier1' of providers which all
undertake to provide a daily digest value that is fed into the digests of
each of the others. It is now impossible for any individual provider to
default without that default being seen globally.

-- 
Website: http://hallambaker.com/