Quantum-Safe Group Key Establishment Protocol from Lattice Trapdoors

• 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 keys 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 poten-tial 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. © 2022 by the authors. 

Subject headings

NATURVETENSKAP  -- Data- och informationsvetenskap (hsv//swe)

NATURAL SCIENCES  -- Computer and Information Sciences (hsv//eng)

NATURVETENSKAP  -- Data- och informationsvetenskap -- Datavetenskap (hsv//swe)

NATURAL SCIENCES  -- Computer and Information Sciences -- Computer Sciences (hsv//eng)

Keyword

IoT group key

lattice trapdoors

lattice-based crypotgraphy

lattices

learning with errors

lightweight cryptography

LWE

one-way function

quantum-safe cryptography

short basis

Linear algebra

Quantum computers

Quantum cryptography

Group key

Internet of thing group key

Lattice

Lattice trapdoor

Lattice-based

Light-weight cryptography

One-way functions

Short base

Internet of things

Publication and Content Type

ref (subject category)

art (subject category)