mMIC: Multicast Message Integrity Code for Securing Low-Entropy Control Command

Although Industrial Control Systems (ICSs) continue to evolve with the introduction of Industrial Internet of Thing (IIoT), this advancement also introduces various threats and vulnerabilities in manufacturing industries and critical national infrastructures. In this study, we investigate authenticating control commands sent via multicast to the ICS’s resource-constrained field devices. There are currently three approaches for multicast source-authentication: <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pairwise key, delayed authentication</i>, and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">signature</i>. If the multicast messages are command messages to be processed rapidly by the resource-constrained devices, the multicast source-authentication scheme should meet the following criteria: <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">immediate and per-message authentication, low computational complexity</i> of verifying command messages, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">low communication overhead</i> to suppress message fragmentation, and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">robustness against compromised device attack</i>. However, none of the existing approaches meets all the criteria. To address the multicast source-authentication issues, we design two cryptographic primitives-<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dual function chains</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">infinite hash chain</i>, based on which a multicast source-authentication scheme called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">multicast Message-Integrity Code</i> (mMIC) to protect control commands sent via multicast is constructed. We show that the proposed mMIC meets all the criteria and it can be efficiently implemented with cryptographic hash operation alone. In particular, it is also shown that the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">communication overhead</i> is the most important of the four criteria, since it takes up most of the delay of reception and verification of command messages.