Cryptology ePrint Archive: Report 2017/724

Dynamic and Verifiable Hierarchical Secret Sharing

Giulia Traverso and Denise Demirel and Johannes Buchmann

Abstract: In this work we provide a framework for dynamic secret sharing and present the first dynamic and verifiable hierarchical secret sharing scheme based on Birkhoff interpolation. Since the scheme is dynamic it allows, without reconstructing the message distributed, to add and remove shareholders, to renew shares, and to modify the conditions for accessing the message. Furthermore, each shareholder can verify its share received during these algorithms protecting itself against malicious dealers and shareholders. While these algorithms were already available for classical Lagrange interpolation based secret sharing, corresponding techniques for Birkhoff interpolation based schemes were missing. Note that Birkhoff interpolation is currently the only technique available that allows to construct hierarchical secret sharing schemes that are efficient and allow to provide shares of equal size for all shareholder in the hierarchy. Thus, our scheme is an important contribution to hierarchical secret sharing.

Category / Keywords: cryptographic protocols / hierarchical secret sharing, distributed storage, cloud computing, long-term security, Birkhoff interpolation, proactive secret sharing

Original Publication (in the same form): 9th International Conference of Information Theoretic Security (ICITS2016)

Date: received 25 Jul 2017

Contact author: gtraverso at cdc informatik tu-darmstadt de

Available format(s): PDF | BibTeX Citation

Version: 20170731:154337 (All versions of this report)

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