International Journal on Advanced Science, Engineering and Information Technology, Vol. 8 (2018) No. 5, DOI:10.18517/ijaseit.8.5.5046

Implementation of an eCK-secure Key Exchange Protocol for OpenSSL

Janaka Alawatugoda, Seralathan Vivekaanathan, Nishen Peiris, Chamitha Wickramasinghe, Chai Wen Chuah

Abstract

Security models have been developed over time to analyze the security of two-party authenticated key exchange (AKE) protocols. LaMacchia et al. (ProSec 2007) presented a strong security model for AKE protocols, namely the extended Canetti-Krawczyk (eCK) model, addressing wide range of real-world attack scenarios. They constructed a protocol called NAXOS, that is proven-secure in the eCK model. In order to satisfy the eCK security, the NAXOS protocol uses a hash function to combine the long-term secret key and the ephemeral secret key, which is often called as “NAXOS-trick”. However, for the NAXOS-trick-based protocols, the way of leakage modelled in the eCK model leads to an unnatural assumption of leak-free computation of the hash function. Precisely, the eCK model allows the attacker to reveal the ephemeral key while the output of the NAXOS-trick computation remains safe (leak-free). In a recent work of Alawatugoda et al. (IMA Cryptography and Coding 2015), a NAXOS-trick-free eCK-secure AKE protocol is presented, namely protocol P1. In this work, we implement the protocol P1 to be used with the widely-used OpenSSL cryptographic library. OpenSSL implementations are widely used with the real-world security protocol suites, such as Security Socket Layer (SSL) and Transport Layer Security (TLS). As per best of our knowledge, this is the first implementation of a eCK-secure key exchange protocol for the OpenSSL library. Thus, we open up the direction to use the recent advancements of cryptography for real-world Internet communication.

Keywords:

Authenticated key exchange; eCK mode; OpenSSL.

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