Network message authentication and verification

The present application relates to an apparatus and method of authenticating and verifying a message frame on a multi-master access bus with message broadcasting. Logic bus identifier, LID, are associated with each one of a several logical groups of nodes out of a plurality of nodes connected to the multi-master access bus. A key is assigned to each logical group. The keys assigned to different logical groups differ from each other. For message authentication, a logic bus identifier, LID is provided and a key associated with the logic bus identifier, LID, is retrieved. A cryptographic hash value, MAC, is generated using the retrieved key and based on at least the logic bus identifier, LID. A message frame is composed, which comprises the logic bus identifier, LID, and the cryptographic hash value, MAC. For message verification, a message frame is received, which comprises at least a logic bus identifier, LID, and a cryptographic hash value, MAC. A key is retrieved, which is associated with the logic bus identifier, LID, extracted from the frame. A cryptographic verification hash value, VAC, is generated using the retrieved key and based on at least the logic bus identifier, LID. The cryptographic verification hash value, VAC, and the cryptographic hash value, MAC, extracted from the frame are compared. The received message frame is forward for further processing as a legitimate message frame.