Description
Modern industrial machinery often requires various computer systems to com-
municate securely. Bus systems, such as Controller Area Network (CAN) and
Automotive Ethernet, are utilized in many industrial contexts to network the
devices. To guarantee the integrity and authenticity of messages sent on the bus,
Message Authentication Codes (MACs) can be used. MACs can only be generated
if a key is shared amongst all authentic devices on the bus. Hence, a Group Key
Agreement (GKA) protocol is needed to share the key amongst the devices.
This thesis aims to identify an authenticated and fully distributed Group Key
Agreement protocol that is suitable for industrial use cases. Hence, the thesis
begins by analyzing the requirements of an industrial user. These requirements
are used to identify a suitable GKA protocol that can fulfill the requirements set
by the use case.
This thesis introduces IndusTreeal GKA, which is a scalable, dynamic, and
distributed GKA based on TreeKEM. The protocol is not only able to provide
Post-Compromise Security (PCS) and Forward Secrecy (FS), but also can prevent
most attacks conducted by a Dolev Yao adversary. Furthermore, the protocol
will take quantum-safety into account, providing both cryptographic agility and
protection against Harvest Now Decrypt Later (HNDL) attacks. Due to the
resource-constrained nature of most industrial machinery, the protocol’s commu-
nication, storage, and computational overheads are calculated. This analysis can
be used to compare IndusTreeal GKA to other protocols.
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Thesis topic in co-operation with the Fraunhofer Institute for Applied and Integrated Security AISEC, Garching