d. Spare keys and combination numbers should be treated as classified
in some cases.
This would occur if their locks are used for classified
e. Maintain a key access list in the key storage container.
f. At the end of each shift, check key containers and contents.
depository must be used to secure keys during nonoperational hours.
a. Key locks. A key lock can be picked by an expert in a few minutes.
Loss and compromise of a key and the case in which an impression may be made
should be considered. Determine the security value of such a key-type lock.
b. Conventional Combination Locks.
This type lock may be opened by a
skillful person. He may be able to determine the settings of the tumblers of
a common three-position, dial-type combination lock. He does so through his
An expert can open an average conventional combination lock in a
c. Manipulation-Resistant Combination Locks.
lock is specially designed. The opening lever does not come in contact with
the tumblers until the combination has been set.
d. Other Combination Locks.
Combination locks with four or more
tumblers may be desirable.
These can be used for containers of highly
e. Relocking Devices. A relocking device on a safe or vault door gives
an added degree of security.
Such a device increases the difficulty of
opening a combination lock container. Forced entry is often accomplished by
punching, drilling, or blocking the lock or its parts. A relocking device is
recommended for heavy safes and vaults.
f. Interchangeable Cores. The interchangeable core system uses a type
of lock with a removable core that can be replaced by another, using a
different key. A control key is used for core removal and maintenance and is
square shaped at the end. The operator key is used for opening and locking
only and is rounded at the end. Its main features include the following:
(1) Cores may be quickly replaced.
locks and keys when their security is compromised.
(2) Interchangeable cores are economical.
This is due to reduction
in maintenance costs and new lock expense.
(3) Such a system is flexible and can be engineered to the needs of