Quantum-Safe Group Key Establishment Protocol from Lattice Trapdoors

Teklay Gebremichael, Mikael Gidlund, Gerhard P. Hancke, Ulf Jennehag
2022 Sensors  
Group communication enables Internet of Things (IoT) devices to communicate in an efficient and fast manner. In most instances, a group message needs to be encrypted using a cryptographic key that only devices in the group know. In this paper, we address the problem of establishing such a key using a lattice-based one-way function, which can easily be inverted using a suitably designed lattice trapdoor. Using the notion of a bad/good basis, we present a new method of coupling multiple private
more » ... ys into a single public key, which is then used for encrypting a group message. The protocol has the apparent advantage of having a conjectured resistance against potential quantum-computer-based attacks. All functions—key establishment, session key update, node addition, encryption, and decryption—are effected in constant time, using simple linear-algebra operations, making the protocol suitable for resource-constrained IoT networks. We show how a cryptographic session group key can be constructed on the fly by a user with legitimate credentials, making node-capture-type attacks impractical. The protocol also incorporates a mechanism for node addition and session-key generation in a forward- and backward-secrecy-preserving manner.
doi:10.3390/s22114148 pmid:35684771 pmcid:PMC9185647 fatcat:ffxmzzhzbbesrltvxjnezmhznm