Changing thresholds in the absence of secure channels

Keith M. Martin, Josef Pieprzyk, Reihaneh Safavi-Naini, Huaxiong Wang

Research output: Chapter in Book/Report/Conference proceedingChapter

28 Citations (Scopus)


The ways the threshold parameter can be modified after the setup of a secret sharing scheme is the main theme of this work. The considerations are limited to the case when there are no secure channels. First we motivate the problem and discuss methods of threshold change when the dealer is still active and can use broadcasting to implement the change required. Next we study the case when participants themselves initiate the change of threshold without the dealer’s help. A general model for threshold changeable secret sharing is developed and two constructions are given. The first generic construction allows the design of a threshold changeable secret sharing scheme which can be implemented using the Shamir approach. The second construction is geometrical in nature and is optimal in terms of the size of shares. The work is concluded by showing that any threshold scheme can be given some degree of threshold change capability.

Original languageEnglish
Title of host publicationInformation Security and Privacy
Subtitle of host publication4th Australasian Conference, ACISP’99 Wollongong, NSW, Australia, April 7–9, 1999 Proceedings
EditorsJosef Pieprzyk, Rei Safavi-Naini, Jennifer Seberry
Place of PublicationBerlin
PublisherSpringer, Springer Nature
Number of pages15
ISBN (Electronic)9783540489702
ISBN (Print)9783540657569
Publication statusPublished - 1999
Event4th Australasian Conference on Information Security and Privacy, ACISP - 1999 - Wollongong, Australia
Duration: 7 Apr 19999 Apr 1999

Publication series

NameLecture Notes in Computer Science
PublisherSpringer Berlin Heidelberg
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Other4th Australasian Conference on Information Security and Privacy, ACISP - 1999


  • Geometrical Secret Sharing
  • Secret Sharing
  • Shamir Secret Sharing
  • Threshold Changeable Secret Sharing

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