Paper 2014/833

Efficient Distributed Tag-Based Encryption and its Application to Group Signatures with Efficient Distributed Traceability

Essam Ghadafi

Abstract

In this work, we first formalize the notion of dynamic group signatures with distributed traceability, where the capability to trace signatures is distributed among $n$ managers without requiring any interaction. This ensures that only the participation of all tracing managers permits tracing a signature, which reduces the trust placed in a single tracing manager. The threshold variant follows easily from our definitions and constructions. Our model offers strong security requirements. Our second contribution is a generic construction for the notion which has a concurrent join protocol, meets strong security requirements, and offers efficient traceability, i.e.\ without requiring tracing managers to produce expensive zero-knowledge proofs for tracing correctness. To dispense with the expensive zero-knowledge proofs required in the tracing, we deploy a distributed tag-based encryption with public verifiability. Finally, we provide some concrete instantiations, which, to the best of our knowledge, are the first efficient provably secure realizations in the standard model simultaneously offering all the aforementioned properties. To realize our constructions efficiently, we construct an efficient distributed (and threshold) tag-based encryption scheme that works in the efficient Type-III asymmetric bilinear groups. Our distributed tag-based encryption scheme yields short ciphertexts (only 1280 bits at 128-bit security), and is secure under an existing variant of the standard decisional linear assumption. Our tag-based encryption scheme is of independent interest and is useful for many applications beyond the scope of this paper. As a special case of our distributed tag-based encryption scheme, we get an efficient tag-based encryption scheme in Type-III asymmetric bilinear groups that is secure in the standard model.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Published elsewhere. Major revision. Latincrypt 2014
Keywords
Group signaturesdistributed traceabilitydistributed public-key encryptionstandard model
Contact author(s)
eg6947 @ googlemail com
History
2015-06-21: revised
2014-10-20: received
See all versions
Short URL
https://ia.cr/2014/833
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2014/833,
      author = {Essam Ghadafi},
      title = {Efficient Distributed Tag-Based Encryption and its Application to Group Signatures with Efficient Distributed Traceability},
      howpublished = {Cryptology ePrint Archive, Paper 2014/833},
      year = {2014},
      note = {\url{https://eprint.iacr.org/2014/833}},
      url = {https://eprint.iacr.org/2014/833}
}
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