Master Keying David M. Koenig, CPP

Master Keying Is... n System Of Organizing Numbers –For Cutting Keys –For Pinning Locks n Grouping Of Locks And Keys n Set Of Locks That Are Operated By More Than One Key

Master Keying Provides n Convenience Over Security n Separate Keys For Individual Locks n Keys To Operate Groups Of Locks n Single Key For All Locks In System n Ability To Carry Fewer Keys n Organization Of And Management OF Lock & Key System

Master Keying Disadvantages n Makes Locks Easier To Pick n Small Master Pins Increase Service Issues n Higher Re-keying Cost If GMK Or GGMK Keys Are Lost n More Thought Involved In Administration n Controlled Destruction of Lock Security

Master Keying Terms n KA - Keyed Alike - Several Locks Operated By The Same Key n KD - Keyed Different - Each Lock Operated By It’s Own Key

Master Keying Terms n CK - Change Key –Work Individual Lock n MK - Master Key n GMK - Grand Master Key –Works Large Group Of Locks n GGMK - Great Grand Master Key –Fits All Locks In System

Master Keying Terms n SKD - Single Keyed Different –Lock Set To Change Key Only n NMK - Not Master Keyed –Similar To SKD n Levels - Number Of Different Types Of Keys In System –Example CK-MK-GMK = 3 Level System

Master Keying Terms n Sectional Keyways - Variety Of Key Blank Grove Sizes And Shapes – Divided Into Groups –Some Patterns Are Wider Than Others –Higher Level Patterns Fit Into Multiple Keyways –Allows Cut Numbers To Be Repeated

System Size and Security n 5 Or 6 Pin Chambers (more is better) n Chamber Depths n Pinning Increment (Key / Pin Wear) n How Many Chambers Are Progressed n Angles (Or Other Factor) Employed

System Size and Security n MACS (Maximum Adjacent Cuts) Loss n How Many Masters Employed n Sectional Keyways

Typical System Example n 8 Depths (1-10 Less Two for MK) n Less Increments of Two n Used In 6 Chambers Equals… n 4 To 6th Power Equals… n 4,096 Theoretical Combinations n Less MACS Of 20% n Equals 3,276 Maximum Combinations

Medeco Biaxial System Size n 4 Depths (1-5 Less One Number For GMK) n Used In 6 Chambers Equals… n 4 To 6th Power Equals… n 4,096 Theoretical n Times 9 Sections (Angles) Equals...

Medeco Biaxial System Size n Equals 36,864 Changes Under Single MK n With MACS Loss Of 20% Combinations (Maximum Adjacent Cuts) n Over 29,400 Maximum Combinations n Number Of Chambers Used For Master Keys Reduces Maximum And Determines Availability Within A MK