Dynamic and Verifiable Hierarchical Secret Sharing
Giulia Traverso, Denise Demirel, Johannes Buchmann (Technische Universität Darmstadt)
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 and to other techniques using this primitive, such as social secret sharing based cloud storage.
9th International Conference on Information Theoretic Security (ICITS 2016) (http://www.icits2016.com/)
Place and Date
Tacoma, Washington, USA, 9-12 August 2016