Authenticated key exchange under bad randomness

Authors

Guomin Yang, University of WollongongFollow
Shanshan Duan, University of California San Diego
Duncan Wong, City University of Hong KongFollow
Chik How Tan, National University of Singapore
Huaxiong Wang, Nanyang Technological University

RIS ID

89163

Publication Details

Yang, G., Duan, S., Wong, D., Tan, C. & Wang, H. (2011). Authenticated key exchange under bad randomness. In G. Danezis (Eds.), Financial Cryptography and Data Security Conference: 15th International Conference (pp. 1-23). Germany: Springer.

Abstract

We initiate the formal study on authenticated key exchange (AKE) under bad randomness. This could happen when (1) an adversary compromises the randomness source and hence directly controls the randomness of each AKE session; and (2) the randomness repeats in different AKE sessions due to reset attacks.We construct two formal security models, Reset-1 and Reset-2, to capture these two bad randomness situations respectively, and investigate the security of some widely used AKE protocols in these models by showing that they become insecure when the adversary is able to manipulate the randomness. On the positive side, we propose simple but generic methods to make AKE protocols secure in Reset-1 and Reset-2 models. The methods work in a modular way: first, we strengthen a widely used AKE protocol to achieve Reset-2 security, then we show how to transform any Reset-2 secure AKE protocol to a new one which also satisfies Reset-1 security.