The eFUSE array contains a block of 256 eFUSEs that can provide a key to the AES-GCM cryptographic engine. This block of eFUSEs has dedicated read and write disables controlled by additional eFUSEs. The eFUSE key can be stored in plain text form (red), encrypted form (black), or the eFUSE key, in certain devices, can also be stored in gray form (encrypted with the family key).