Multipoint-to-Multipoint Secure-Messaging with Threshold-Regulated Authorisation and Sabotage Detection

  • Alwyn Goh
  • David C. L. Ngo
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 2828)


This paper presents multi-user protocol-extensions for Schnorr/Nyberg-Ruepple (NR) signatures and Zheng signcryption, both of which are elliptic curve (EC)/discrete logarithmic (DL) formulations. Our extension methodology is based on k-of-n threshold cryptography—with Shamir polynomial parameterisation and Feldman-Pedersen verification–resulting in multi-sender Schnorr-NR (SNR) and multi-sender/receiver Zheng-NR (ZNR) protocols, all of which are interoperable with their single-user base formulations. The ZNR protocol-extensions are compared with the earlier Takaragi et al multi-user sign-encryption, which is extended from a base-protocol with two random key-pairs following the usual specification of one each of signing and encryption. Both single and double-pair formulations are analysed from the viewpoint of EC equivalence (EQ) establishment, which is required for rigorous multi-sender functionality. We outline a rectification to the original Takaragi et al formulation; thereby enabling parameter-share verification, but at significantly increased overheads. This enables comprehensive equivalent-functionality comparisons with the various multi-user ZNR protocol-extensions. The single-pair ZNR approach is shown to be significantly more efficient, in some cases demonstrating a two/three-fold advantage.


Elliptic Curve Signature Scheme Encryption Operation Threshold Cryptography Multisignature Scheme 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© IFIP International Federation for Information Processing 2003

Authors and Affiliations

  • Alwyn Goh
    • 1
  • David C. L. Ngo
    • 2
  1. 1.Corentix LaboratoriesPetaling JayaMalaysia
  2. 2.Faculty of Information Science & TechnologyMultimedia UniversityMelakaMalaysia

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