Practical Round-Optimal Blind Signatures in the Standard Model from Weaker Assumptions

Title

Practical Round-Optimal Blind Signatures in the Standard Model from Weaker Assumptions

Authors

Georg Fuchsbauer (École normale supérieure, Paris) and Christian Hanser (IAIK, Graz University of Technology) and Chethan Kamath (Institute of Science and Technology Austria) and Daniel Slamanig (IAIK, Graz University of Technology).

Abstract

At Crypto'15 Fuchsbauer, Hanser and Slamanig (FHS) presented the first standard-model construction of efficient round-optimal blind signatures that does not require complexity leveraging. It is conceptually simple and builds on the primitive of structure-preserving signatures on equivalence classes (SPS-EQ). FHS prove the unforgeability of their scheme assuming EUF-CMA security of the SPS-EQ scheme and hardness of a version of the DH inversion problem. Blindness under adversarially chosen keys is proven under an interactive variant of the DDH assumption.
We propose a variant of their scheme whose blindness can be proven under a non-interactive assumption, namely a variant of the bilinear DDH assumption. We moreover prove its unforgeability assuming only unforgeability of the underlying SPS-EQ but no additional assumptions as needed for the FHS scheme.

Venue

10th Conference on Security and Cryptography for Networks, SNC 2016 (http://scn.dia.unisa.it)

Place and Date

Amalfi, Italy, August 31 - September 2, 2016.

Publication Reference

Georg Fuchsbauer, Christian Hanser, Chethan Kamath, and Daniel Slamanig. "Practical Round-Optimal Blind Signatures in the Standard Model from Weaker Assumptions". In Security and Cryptography for Networks - 10th International Conference, SCN 2016, Amalfi, Italy, August 31 - September 2, 2016. Proceedings

Bibtex

@inproceedings{fhks16,
 Title     = {Practical Round-Optimal Blind Signatures in the Standard Model from Weaker Assumptions},
 Author    = {Georg Fuchsbauer and Christian Hanser and Chethan Kamath and Daniel Slamanig},
 Booktitle = {Security and Cryptography for Networks - 10th International Conference, SCN 2016, Amalfi, Italy, August 31 - September 2, 2016. Proceedings},
 year      = {2016},
 Publisher = {Springer}
 }