Cryptology ePrint Archive: Report 2021/1156

Evolving Secret Sharing in Almost Semi-honest Model

Jyotirmoy Pramanik and Avishek Adhikari

Abstract: Evolving secret sharing is a special kind of secret sharing where the number of shareholders is not known beforehand, i.e., at time t = 0. In classical secret sharing such a restriction was assumed inherently i.e., the the number of shareholders was given to the dealerís algorithm as an input. Evolving secret sharing relaxes this condition. Pramanik and Adhikari left an open problem regarding malicious shareholders in the evolving setup, which we answer in this paper. We introduce a new cheating model, called the almost semi-honest model, where a shareholder who joins later can check the authenticity of share of previous ones. We use collision resistant hash function to construct such a secret sharing scheme with malicious node identification. Moreover, our scheme preserves the share size of Komargodski et al. (TCC 2016).

Category / Keywords: cryptographic protocols / Secret Sharing, Evolving, Malicious, Collision resistance.

Date: received 10 Sep 2021

Contact author: jyotirmoy pramanik2 at gmail com, avishek adh at gmail com

Available format(s): PDF | BibTeX Citation

Version: 20210914:174917 (All versions of this report)

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