Paper 2002/024

Timed Release of Standard Digital Signatures

Juan Garay and Markus Jakobsson

Abstract

In this paper we investigate the timed release of standard digital signatures, and demonstrate how to do it for RSA, Schnorr and DSA signatures. Such signatures, once released, cannot be distinguished from signatures of the same type obtained without a timed release, making it transparent to an observer of the end result. While previous work has allowed timed release of signatures, these have not been standard, but special-purpose signatures. Building on the recent work by Boneh and Naor on timed commitments, we introduce the notion of a reusable time-line, which, besides allowing the release of standard signatures, lowers the session costs of existing timed applications.