1.1.6 Persistent Latch

The Persistent Latch is a single bit of volatile memory used to indicate to the device that an associated key has been enabled for use with cryptographic functions. It can retain its state as long as the V_CC remains above 2V. It is always set to low on power-up and can be manipulated using various operations. When the key in a slot is linked to the Persistent Latch, a Persistent Latch state activates/deactivates the key in the slot. There are four ways to control the Persistent Latch: volatile key usage, secure boot, authorization output and intrusion detection. When one of the above methods is run successfully, the Persistent Latch will be set, thus enabling the key in the designated slot.