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Foundations of fully dynamic group signatures

Bootle, Jonathan; Cerulli, Andrea; Chaidos, Pyrros; Ghadafi, Essam; Groth, Jens


Jonathan Bootle

Andrea Cerulli

Pyrros Chaidos

Essam Ghadafi
Senior Lecturer in Computer Science

Jens Groth


Group signatures are a central cryptographic primitive that has received a considerable amount of attention from the cryptographic community. They allow members of a group to anonymously sign on behalf of the group. Membership is overseen by a designated group manager. There is also a tracing authority that can revoke anonymity by revealing the identity of the signer if and when needed, to enforce accountability and deter abuse. For the primitive to be applicable in practice, it needs to support fully dynamic groups, i.e. users can join and leave at any time. In this work we take a close look at existing security definitions for fully dynamic group signatures. We identify a number of shortcomings in existing security definitions and fill the gap by providing a formal rigorous security model for the primitive. Our model is general and is not tailored towards a specific design paradigm and can therefore, as we show, be used to argue about the security of different existing constructions following different design paradigms. Our definitions are stringent and when possible incorporate protection against maliciously chosen keys. In the process, we identify a subtle issue inherent to one design paradigm, where new members might try to implicate older ones by means of back-dated signatures. This is not captured by existing models. We propose some inexpensive fixes for some existing constructions to avoid the issue.


Bootle, J., Cerulli, A., Chaidos, P., Ghadafi, E., & Groth, J. (2016). Foundations of fully dynamic group signatures. In Applied Cryptography and Network Security. , (117-136).

Conference Name Applied Cryptography and Network Security 14th International Conference, ACNS 2016
Start Date Jun 19, 2016
End Date Jun 22, 2016
Acceptance Date Jun 9, 2016
Online Publication Date Jun 9, 2016
Publication Date Jun 9, 2016
Deposit Date Mar 24, 2017
Publisher Springer Verlag (Germany)
Volume 9696
Pages 117-136
Series Title Lecture Notes in Computer Science
Series ISSN 0302-9743
Book Title Applied Cryptography and Network Security
ISBN 9783319395548
Keywords group signatures, security definitions
Public URL
Publisher URL


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