Two More Efficient Variants of the J-PAKE Protocol

Conference paper

DOI: 10.1007/978-3-319-39555-5_4

Part of the Lecture Notes in Computer Science book series (LNCS, volume 9696)
Cite this paper as:
Lancrenon J., Škrobot M., Tang Q. (2016) Two More Efficient Variants of the J-PAKE Protocol. In: Manulis M., Sadeghi AR., Schneider S. (eds) Applied Cryptography and Network Security. ACNS 2016. Lecture Notes in Computer Science, vol 9696. Springer, Cham


Recently, the password-authenticated key exchange protocol J-PAKE of Hao and Ryan (Workshop on Security Protocols 2008) was formally proven secure in the algebraic adversary model by Abdalla et al. (IEEE S&P 2015). In this paper, we propose and examine two variants of J-PAKE - which we call RO-J-PAKE and CRS-J-PAKE - that each makes the use of two less zero-knowledge proofs than the original protocol. We show that they are provably secure following a similar strategy to that of Abdalla et al. We also study their efficiency as compared to J-PAKE’s, also taking into account how the groups are chosen. Namely, we treat the cases of subgroups of finite fields and elliptic curves. Our work reveals that, for subgroups of finite fields, CRS-J-PAKE is indeed more efficient than J-PAKE, while RO-J-PAKE is much less efficient. On the other hand, when instantiated with elliptic curves, both RO-J-PAKE and CRS-J-PAKE are more efficient than J-PAKE, with CRS-J-PAKE being the best of the three. Regardless of implementation, we note that RO-J-PAKE enjoys a looser security reduction than both J-PAKE and CRS-J-PAKE. CRS-J-PAKE has the tightest security proof, but relies on an additional trust assumption at setup time.


Password-authenticated key exchange J-PAKE Efficiency Random oracle Common reference string Zero-knowledge proof 

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.SnT, University of LuxembourgLuxembourgLuxembourg

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