The new Authentication Service (0x29) of the Unified Diagnostic Services (UDS) [ISO 14229]

[@emesde]

I think these services don't grant a acces to a specific user, they grant access to those function on the CAN bus, not matter who sends them at the moment. Correct?

[@CyberSecuritybyITKEngineering]

You are right, anyone on the bus can access the diagnostic functions after a user or tester is authenticated. To prevent this, an additional secure session need to be established. This, however, would be an extension to the standardized authentication mechanism.

[@emesde]

@@CyberSecuritybyITKEngineering I think better move to CAN FD, the can data payload is limited already .

[@rahulsaurav3933]

can you please explain the request format for SID 29.

[@CyberSecuritybyITKEngineering]

You can find the message format for all requests and responses in the ISO 14229-1:2020 standard. They contain a good description of available parameters and message fields for the authentication service as well.