Encrypted symmetric keys are managed in key blocks that cryptographically bind the key's usage to the key, by phases: internal connections and storage in service-provider environments from 1 June 2019, external connections to associations and networks from 1 January 2023, and merchant hosts, POS devices and ATMs from 1 January 2025; acceptable methods include a MAC over the clear attributes and the enciphered key, a signature, or a method where the key and attributes cannot be separated without detection.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.