54.5.5.7 Get Key Operation

The Get Key operation derives a key from the intrinsic PUF key and the provided context. The context also defines the length of the derived key. The key is provided to the defined destination interface. Depending on the state of the PUF controller, the allowed destinations may be limited as described in Context Specification for Key Operations. When an invalid destination is defined (all bits 0, or more than one bit 1), the command is rejected.

Bits 3:0 of the user_context_0 word of the context are passed to the Key Index register (PUF_KEY_INDEX). When the key is output to PUF_DOR, the value can be used to transfer the key to a specific process or function.