A New Secret Sharing Scheme Based on the Multi-Dealer

Cheng GUO  Mingchu LI  Kouichi SAKURAI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E92-A   No.5   pp.1373-1378
Publication Date: 2009/05/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E92.A.1373
Print ISSN: 0916-8508
Type of Manuscript: LETTER
Category: Cryptography and Information Security
secret sharing,  multi-dealer,  factoring problem,  discrete logarithm,  threshold scheme,  

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Almost all the existing secret sharing schemes are based on a single dealer. Maybe in some situations, the secret needs to be maintained by multiple dealers. In this paper, we proposed a novel secret sharing scheme based on the multi-dealer by means of Shamir's threshold scheme and T. Okamoto and S. Uchiyama's public-key cryptosystem. Multiple dealers can commonly maintain the secret and the secret can be dynamically renewed by any dealer. Meanwhile, the reusable secret shadows just needs to be distributed only once. In the secret updated phase, the dealer just needs to publish a little public information instead of redistributing the new secret shadows. Its security is based on the security of Shamir's threshold scheme and the intractability of factoring problem and discrete logarithm problem.