A note on the strong authenticated key exchange with auxiliary inputs

Authors

Rongmao Chen, National University of Defense Technology ChangshaFollow
Yi Mu, University of WollongongFollow
Guomin Yang, University of WollongongFollow
Willy Susilo, University of WollongongFollow
Fuchun Guo, University of WollongongFollow
Yang Zheng, University of WollongongFollow

RIS ID

115676

Publication Details

Chen, R., Mu, Y., Yang, G., Susilo, W., Guo, F. & Zheng, Y. (2017). A note on the strong authenticated key exchange with auxiliary inputs. Designs, Codes, and Cryptography, 85 175-178.

Abstract

Recently, Chen et al. proposed a framework for authenticated key exchange (AKE) protocols (referred to as CMYSG scheme) in Designs, Codes and Cryptography (available at http://link.springer.com/article/10.1007/s10623-016-0295-3). It is claimed that the proposed AKE protocol is secure in a new leakage-resilient eCK model w.r.t. auxiliary inputs (AI-LR-eCK). The main tool used for the generic construction is the smooth projective hash function (SPHF). In this note, we revisit the CMYSG scheme and point out a subtle flaw in the original security proof. Precisely, we show that the AI-LR-eCK security of the proposed construction cannot be successfully reduced to a pseudo-random SPHF and thus the CMYSG scheme is not secure as claimed. To restore the security proof, we replace the underlying typical SPHF with a 2-smooth SPHF, and show that such a replacement combined with a (Formula presented.) suffices to overcome the subtle flaw.