Cryptology ePrint Archive: Report 2000/027
Accountable Certificate Management using Undeniable Attestations
Ahto Buldas and Peeter Laud and Helger Lipmaa
Abstract: This paper initiates a study of accountable certificate management
methods, necessary to support long-term authenticity of digital
documents. Our main contribution is a model for accountable
certificate management, where clients receive attestations
confirming inclusion/removal of their certificates from the database
of valid certificates. We explain why accountability depends on the
inability of the third parties to create contradictory attestations.
After that we define an undeniable attester as a primitive that
provides efficient attestation creation, publishing and
verification, so that it is intractable to create contradictory
attestations. We introduce authenticated search trees and build an
efficient undeniable attester upon them. The proposed system is the
first accountable long-term certificate management system.
Moreover, authenticated search trees can be used in many
security-critical applications instead of the (sorted) hash trees to
reduce trust in the authorities, without decrease in efficiency.
Therefore, the undeniable attester promises looks like a very useful
cryptographic primitive with a wide range of applications.
Category / Keywords: /accountable certificate management, authenticated search trees, attesters, long-term authenticity, non-repudiation, public-key infrastructure, search trees, time-stamping
Publication Info: Revision corresponds to the final publication in <A HREF="http://www.ccs2000.org">ACM CCS '2000</A>.
Date: received 8 Jun 2000, revised 3 Jul 2000, revised 22 Aug 2000, revised 22 Aug 2000
Contact author: helger at tml hut fi
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Version: 20000822:135636 (All versions of this report)
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