HPAKE: Honey Password-Authenticated Key Exchange for Fast and Safer Online Authentication

Password-only authentication is one of the most popular secure mechanisms for real-world online applications. But it easily suffers from a practical threat - password leakage, incurred by external and internal attackers. The external attacker may compromise the password file stored on the authentication server, and the insider may deliberately steal the passwords or inadvertently leak the passwords. So far, there are two main techniques to address the leakage: Augmented password-authentication key exchange (aPAKE) against insiders and honeyword technique for external attackers. But none of them can resist both attacks. To fill the gap, we propose the notion of honey PAKE (HPAKE) that allows the authentication server to detect the password leakage and achieve the security beyond the traditional bound of aPAKE. Further, we build an HPAKE construction on the top of the honeyword mechanism, honey encryption, and OPAQUE which is a standardized aPAKE. We formally analyze the security of our design, achieving the insider resistance and the password breach detection. We implement our design and deploy it in the real environment. The experimental results show that our protocol only costs 71.27 ms for one complete run, within 20.67 ms on computation and 50.6 ms on communication. This means our design is secure and practical for real-world applications.

I. Introduction

Password-only authentication (PoA), which has great advantages on usability and deployability, is one of the most popular online authentication methods [1]. It has been attracting attentions from academia, and recently many research works have been proposed in this field [2], [3], [4]. But PoA does easily suffer from password leakage. Billions of personal and business passwords have been compromised by hackers [5] which yields a considerable amount of users’ privacy leakage and financial loss, for example, Yahoo made 3 billion accounts exposed [6] and it finally agreed to settle for 117.5 million US dollars [7]. The password leakage, in practice, may be caused by: 1) active external attacks (e.g., SQL injection), or 2) the internal design flaws and software bugs (for instance, GitHub records passwords in plaintext [8]). It is not trivial to handle these attacks in the context of PoA.