Updating the Parameters of a Threshold Scheme by Minimal Broadcast

S.  G.  Barwick; W. -A.  Jackson; K.  M.  Martin

Paper 2004/177

Updating the Parameters of a Threshold Scheme by Minimal Broadcast

S. G. Barwick, W. -A. Jackson, and K. M. Martin

Abstract

Threshold schemes allow secret data to be protected amongst a set of participants in such a way that only a pre-specified threshold of participants can reconstruct the secret from private information (shares) distributed to them on system setup using secure channels. We consider the general problem of designing unconditionally secure threshold schemes whose defining parameters (the threshold and the number of participants) can later be changed by using only public channel broadcast messages. In this paper we are interested in the efficiency of such threshold schemes, and seek to minimise storage costs (size of shares) as well as optimise performance in low bandwidth environments by minimising the size of necessary broadcast messages. We prove a number of lower bounds on the smallest size of broadcast message necessary to make general changes to the parameters of a threshold scheme in which each participant already holds shares of minimal size. We establish the tightness of these bounds by demonstrating optimal schemes.

Metadata

Available format(s): PDF
Publication info: Published elsewhere. Unknown where it was published
Keywords: Cryptology secret sharing schemes threshold schemes
Contact author(s): sbarwick @ maths adelaide edu au
History: 2004-07-26: received
Short URL: https://ia.cr/2004/177
License: CC BY

BibTeX

@misc{cryptoeprint:2004/177,
      author = {S.  G.  Barwick and W. -A.  Jackson and K.  M.  Martin},
      title = {Updating the Parameters of a Threshold Scheme by Minimal Broadcast},
      howpublished = {Cryptology {ePrint} Archive, Paper 2004/177},
      year = {2004},
      url = {https://eprint.iacr.org/2004/177}
}