Harvard Theory of Computation Seminar
New Approaches to Digital Evidence
Ueli Maurer, ETH Zurich
Place and Time: FRIDAY 8 September, 2006, Refreshments at 10:45,
talk at 11. Maxwell Dworkin 221.
ABSTRACT
Digital evidence, such as digital signatures, is of crucial
importance in
the emerging digitally operating economy because it is easy to
transmit,
archive, search, and verify. Nevertheless the initial promises
of
the
usefulness of digital signatures were too optimistic. This
calls
for a
systematic treatment of digital evidence. The goal of this talk
is to
provide a foundation for reasoning about digital evidence
systems
and
legislation, thereby identifying the roles and limitations of
digital
evidence, in the apparently simple scenario where it should
prove
that an
entity A agreed to a digital contract d.
Our approach is in sharp contrast to the current general views
documented in
the technical literature and in digital signature legislation.
We
propose an
entirely new view of the concepts of certification,
time-stamping,
revocation, and other trusted services, potentially leading to
new
and more
sound business models for trusted services. Some of the perhaps
provocative
implications of our view are that certificates are generally
irrelevant as
evidence in a dispute, that it is generally irrelevant *when* a
signature
was generated, that a commitment to be liable for digital
evidence
cannot
meaningfully be revoked, and that there is no need for
*mutually*
trusted
authorities like certification authorities. We also propose a
new
type of
digital evidence called digital declarations, based on a digital
recording
of a willful act indicating agreement to a document or contract.
Paper at
ftp://ftp.inf.ethz.ch/pub/crypto/publications/Maurer04.pdf
Ueli Maurer is a Professor of Computer Science in the
Information
Security
and Cryptography Research Group at the Swiss Federal Institute
of
Technology
(ETH) Zurich.