POST-QUANTUM CRYPTOGRAPHY FOR HEALTHCARE: A NUMBER THEORY BASED TWO-FACTOR MUTUAL AUTHENTICATION AND KEY EXCHANGE PROTOCOL OVER LATTICES FOR TMIS
Sidoine Djimnaibeye, Aminata Ngom, Djiby Sow · Advances and Applications in Discrete Mathematics · 2023
The telecare medical information system (TMIS) allows patients to access health services from their homes. It is therefore necessary to preserve privacy of the patient and to secure the communications between the patient/user and the gateway/server for TMIS (Gw, briefly). We propose a new ring learning with error (RLWE) based on two-factor authentication and key exchange protocol, post-quantum secure, for healthcare platform by using a similar protocol of Ding et al. at Cryptographers’ Track at the RSA Conference in 2017 [32]. Our protocol involves four phases: user registration phase, login phase, mutual authentication and key agreement phase, and user’s password change phase. Gw has a long-term public key $\left(p_s\right)$ and a private key $\left(x_s\right)$. The user has a password $p w d$. The user's personal device/smartphone (PD, briefly) has a long-term secret key $x_u$. This secret key $x_u$ is encrypted by $p w d$ and stored on $\mathrm{PD}$. The $\mathrm{PD}$ and the $\mathrm{Gw}$ share a long-term password $S$. This shared password $S$ is calculated by Gw from its secret $x_s$ and the hash of the user's id $\left(H_1\left(\ldots, i d, x_u\right)\right)$. Gw sends $S$ to PD through a secure channel. At user's side, $S$ is encrypted (stored on PD) with $p w d$ and the PD's long-term secret key $x_u$. Note that $S$ and id are not stored on $\mathrm{Gw}$. For privacy, all the information required for user's authentication are securely stored on PD and no information of the user is stored on $\mathrm{Gw}$. $p w d$ can be frequently changed offline (inside the PD). Received: January 7, 2023Accepted: February 25, 2023