CML Keying Systems & Key Control 3 — Questions and Answers
Question 1: What is the purpose of a 'key control log' in a high-security facility?
- To track the bitting specifications of all keys in the system
- To record the issuance, return, and current holder of each key (Correct answer)
- To document the rekeying history of each lock
- To list all authorized key duplication facilities
Correct answer: To record the issuance, return, and current holder of each key
A key control log provides an auditable chain of custody for each key, recording who received it, when, and confirming its return.
Question 2: Which type of key system uses a sidebar in addition to standard pin tumblers to provide higher security?
- Warded key systems
- Disc detainer systems
- High-security pin tumbler systems like Medeco or Mul-T-Lock (Correct answer)
- Lever tumbler systems
Correct answer: High-security pin tumbler systems like Medeco or Mul-T-Lock
High-security cylinders like Medeco use a sidebar mechanism that requires correct key cuts AND proper rotation of pins, making picking and bumping extremely difficult.
Question 3: In a grand master key system, the hierarchy from highest to lowest access is:
- Change key → master key → grand master key
- Grand master key → master key → change key (Correct answer)
- Master key → grand master key → change key
- Change key → grand master key → master key
Correct answer: Grand master key → master key → change key
The grand master key has the broadest access (all locks), master keys operate subgroups, and change keys open only individual locks.
Question 4: What is 'key bitting specification' (KBS)?
- The document listing all possible cuts for a given key blank
- The manufacturer's published data defining cut depths, spacing, and angles for a specific key series (Correct answer)
- The number of cuts on any given key
- The tolerance range for acceptable key duplication
Correct answer: The manufacturer's published data defining cut depths, spacing, and angles for a specific key series
The key bitting specification is the manufacturer's technical document defining all parameters needed to cut keys correctly, including depths, spacing, and angles.
Question 5: A 'restricted keyway' provides key control primarily because:
- The key blanks are made of hardened steel that cannot be cut by standard machines
- The key blank profile is only available to authorized dealers who verify purchaser identity (Correct answer)
- The keyway has additional warding that standard keys cannot enter
- The cylinder requires a special tool to remove for rekeying
Correct answer: The key blank profile is only available to authorized dealers who verify purchaser identity
Restricted keyways control duplication by making the key blanks available only through authorized channels that require identity verification and maintain records.
Question 6: What is the risk of having too many 'master wafers' in a pin tumbler cylinder?
- The cylinder becomes harder to install
- Increased risk of false keys (unauthorized keys accidentally operating the lock) (Correct answer)
- The master key wears out faster
- The change key requires more cuts
Correct answer: Increased risk of false keys (unauthorized keys accidentally operating the lock)
Each master wafer added to a pin stack creates an additional shear line, increasing the probability that non-authorized keys will accidentally align and open the lock.
Question 7: When performing a 'key system audit,' a locksmith should first:
- Rekey all locks that cannot be accounted for
- Compare the key control log against the actual issued keys and lock inventory (Correct answer)
- Replace all restricted key blanks with standard blanks for cost savings
- Install new cylinders in all high-security areas
Correct answer: Compare the key control log against the actual issued keys and lock inventory
An audit begins by reconciling records — verifying that documented key assignments match physical keys in circulation and locks in the field.
CML Keying Systems & Key Control 3
What is the purpose of a 'key control log' in a high-security facility?