Enabling Anonymous Authenticated Encryption with a Novel Anonymous Authenticated Credential Key Agreement (AACKA)
Raphael Schermann, Rainer Urian, Ronald Toegl, Holger Bock, Christian Steger · 2022
Anonymous credential schemes based on elliptic curve pairings are often used to implement privacy-friendly cryptographic protocols, with Direct Anonymous Attestation and Enhanced Privacy IDentification being the most prominent anonymous credential schemes. However, all those schemes are signature-based and do not immediately provide for agreement of (symmetric) encryption keys.In this paper we present a scheme for Anonymous Authenticated Credential Key Agreement, which can be used in anonymously authenticated encryption schemes. This novel building-block combines Camenisch-Lysyanskaya credentials with elliptic curve Diffie-Hellman key agreement.We show how the Authenticated Anonymous Key Agreement protocol can be used to design an anonymous credential based Elliptic Curve Integrated Encryption scheme and argue that it is more efficient than conventional hybrid approaches. We show the applicability of our scheme on performance-restricted Internet of Things devices in Cloud-, Fog-, or Edge-Computing scenarios. In particular, we provide an implementation and a performance evaluation for a standard-compliant Java Card 3.1 device.