Long-Term Secure Commitments via Extractable-Binding Commitments

Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 10342)

Abstract

Cryptographic commitments are either unconditionally hiding or unconditionally binding, but cannot be both. As a consequence, the security of commonly used commitment schemes is threatened in the long-term, when adversaries become computationally much more powerful. We improve over this situation by putting forward a new notion of commitment schemes, so called long-term commitment schemes. These schemes allow for long-term protection because they allow to adjust the protection level after the initial commitment. We also present a construction of a long-term commitment scheme. Unfortunately, it seems impossible to prove the security of such a scheme using the traditional commitment binding definition. Therefore, we put forward a new notion of binding commitments, so called extractable-binding commitments, and use this notion to establish a security proof for our proposed long-term commitment scheme.

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Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  • Ahto Buldas
    • 1
    • 2
  • Matthias Geihs
    • 3
  • Johannes Buchmann
    • 3
  1. 1.Tallinn University of TechnologyTallinnEstonia
  2. 2.Cybernetica ASTallinnEstonia
  3. 3.Darmstadt University of TechnologyDarmstadtGermany

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