The control system must be able to protect information against alteration while it is being transmitted. RE 1 requires cryptographic mechanisms to recognise changes to information in transit, unless alternative physical measures protect it; the ISAGCA paper describes the authentication of communication as an SL 2 capability through the 4-2 counterpart.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.