Resumen
Continuous authentication enhances security by re-verifying a user?s validity during the active session. It utilizes data about users? behavioral actions and contextual information to authenticate them continuously. Such data contain information about user-sensitive attributes such as gender, age, contextual information, and may also provide information about the user?s emotional states. The collection and processing of sensitive data cause privacy concerns. In this paper, we propose two efficient protocols that enable privacy-preserving continuous authentication. The contribution is to prevent the disclosure of user-sensitive attributes using partial homomorphic cryptographic primitives and reveal only the aggregated result without the explicit use of decryption. The protocols complete an authentication decision in a single unidirectional transmission and have very low communication and computation costs with no degradation in biometric performance.