LPbT-SSO: Password-Based Threshold Single-Sign-On Authentication From LWE

In networks, clients access various servers. Servers need to authenticate clients' identities and provide services to clients who pass the authentication. Password-based threshold single-sign-on authentication (PbT-SSO) delegates multiple identity servers to authenticate a client with the client's password, and issue a token for subsequent access. However, existing PbT-SSO schemes are based on conventional hardness problems, which are vulnerable to adversaries equipped with quantum computers in the near future. Once quantum computers are accessible, adversaries can retrieve passwords by off-line dictionary guessing attacks (DGA) from the credentials of clients' passwords. Moreover, quantum adversaries can derive identity servers' secret from public information and further forge tokens with the secret. Motivated by these issues, we propose a password-based threshold single-sign-on authentication from learning with errors problem (LWE), dubbed LPbT-SSO, which is resistant to quantum attacks. LPbT-SSO evaluates a one-way function of passwords, and takes the function outputs as credentials. Since the function is grounded on LWE problem intractable for quantum computation, quantum adversaries cannot recover passwords by off-line DGA. Additionally, LPbT-SSO leverages a lattice-based threshold signature scheme to issue tokens, and guarantees that no adversary can forge a valid token. The comprehensive performance evaluation demonstrates that LPbT-SSO is efficient in terms of computation, storage, and communication costs.