Optimally Efficient Accountable Time-Stamping

  • Ahto Buldas
  • Helger Lipmaa
  • Berry Schoenmakers
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1751)

Abstract

Efficient secure time-stamping schemes employ a 2-level approach in which the time-stamping service operates in rounds. We say that a time-stamping service is accountable if if it makes the TSA and other authorities accountable for their actions by enabling a principal to detect and later prove to a judge any frauds, including attempts to reorder time-stamps from the same round. We investigate the paradigm of time-stamping services based on simply connected graphs, and propose a simple, yet optimal, accountable time-stamping service, using what we call threaded tree schemes. We improve upon the previously best scheme by Buldas and Laud by reducing the size of a time stamp by a factor of about 3.786 and show that our construction is optimal in a strict sense. The new protocols also increase the trustworthiness of the publication process, which takes place at the end of each round.

References

  1. [BdM91]
    Benaloh, J., de Mare, M.: Efficient Broadcast Time-Stamping. Technical Report 1, Clarkson University Department of Mathematics and Computer Science (August 1991)Google Scholar
  2. [BdM93]
    Benaloh, J., de Mare, M.: One-Way Accumulators: A Decentralized Alternative to Digital Signatures (Extended Abstract). In: Helleseth, T. (ed.) EUROCRYPT 1993. LNCS, vol. 765, pp. 274–285. Springer, Heidelberg (1994)Google Scholar
  3. [BHS92]
    Bayer, D., Haber, S.A., Stornetta, W.S.: Improving the Efficiency And Reliability of Digital Time-Stamping. In: Sequences 1991: Methods in Communication, Security, and Computer Science, pp. 329–334. Springer, Heidelberg (1992)Google Scholar
  4. [BL98]
    Buldas, A., Laud, P.: New Linking Schemes for Digital Time-Stamping. In: The 1st International Conference on Information Security and Cryptology, Seoul, Korea, December 18-19, pp. 3–14 (1998); Korea Institute of Information Security and CryptologyGoogle Scholar
  5. [BLLV98]
    Buldas, A., Laud, P., Lipmaa, H., Villemson, J.: Time- Stamping with Binary Linking Schemes. In: Krawczyk, H. (ed.) CRYPTO 1998. LNCS, vol. 1462, pp. 486–501. Springer, Heidelberg (1998)Google Scholar
  6. [HS90]
    Haber, S., Stornetta, W.S.: How to Time-Stamp a Digital Document. In: Menezes, A., Vanstone, S.A. (eds.) CRYPTO 1990. LNCS, vol. 537, pp. 437–455. Springer, Heidelberg (1991)Google Scholar
  7. [HS91]
    Haber, S.A., Stornetta, W.S.: How to Time-Stamp a Digital Document. Journal of Cryptology 3(2), 99–111 (1991)CrossRefGoogle Scholar
  8. [Mer80]
    Merkle, R.C.: Protocols for Public Key Cryptosystems. In: IEEE (ed.) Proceedings of the 1980 Symposium on Security and Privacy, 1109 Spring Street, Suite 300, Silver Spring, MD 20910, USA. IEEE Computer Society Press, Los Alamitos (1980)Google Scholar
  9. [San99]
    Sander, T.: Efficient Accumulators without Trapdoor. In: The Second International Conference on Information and Communication Security, Sydney, Australia, November 9-11 (1999) (to appear)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Ahto Buldas
    • 1
  • Helger Lipmaa
    • 1
  • Berry Schoenmakers
    • 2
  1. 1.Küberneetika ASTallinnEstonia
  2. 2.Dept. of Mathematics and Computing ScienceEindhoven University of TechnologyEindhovenThe Netherlands

Personalised recommendations