International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Democratic Group Signatures with Threshold Traceability

Kefei Chen
Xiangxue Li
Dong Zheng
Changshe Ma
Jianhua Li
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Abstract: Recently, democratic group signatures(DGSs) particularly catch our attention due to their great flexibilities, \emph{i.e}., \emph{no group manager}, \emph{anonymity}, and \emph{individual traceability}. In existing DGS schemes, individual traceability says that any member in the group can reveal the actual signer's identity from a given signature. In this paper, we formally describe the definition of DGS, revisit its security notions by strengthening the requirement for the property of traceability, and present a concrete DGS construction with $(t, n)$-\emph{threshold traceability} which combines the concepts of group signatures and of threshold cryptography. The idea behind the $(t, n)$-threshold traceability is to distribute between $n$ group members the capability of tracing the actual signer such that any subset of not less than $t$ members can jointly reconstruct a secret and reveal the identity of the signer while preserving security even in the presence of an active adversary which can corrupt up to $t-1$ group members.
  title={Democratic Group Signatures with Threshold Traceability},
  booktitle={IACR Eprint archive},
  keywords={public-key cryptography / democratic group signature, anonymity, traceability,threshold traceability},
  note={ 13954 received 12 Mar 2008, last revised 16 Mar 2008},
  author={Kefei  Chen and Xiangxue Li and Dong Zheng and Changshe Ma and Jianhua Li},