A restricted key and a master key describe two different features of a key system.
- Master keying controls which locks each key can open.
- Restriction controls who can obtain additional keys and how they are supplied.
A key system can be master keyed, restricted, both or neither.
This distinction matters when choosing a system. A customer should not assume that a master key is automatically protected against unauthorised duplication, or that every restricted key opens multiple doors.
What is a master key system?
A master key system uses a planned access hierarchy.
Individual keys may open one door or a defined group of doors, while higher-level keys open several predetermined locks.
For example:
- a tenant key may open one apartment and selected common areas
- a cleaner’s key may open common areas
- a maintenance key may open service rooms
- a building manager’s key may open several areas
- a master key may open most or all locks within the system
The hierarchy can be simple or complex, depending on the building and its access requirements.
dormakaba describes a master key system as a key plan in which selected keys can open predefined doors.
The term describes what the keys can access. It does not, by itself, explain whether additional keys are restricted.
What is a restricted key system?
A restricted key system controls the supply of additional keys.
Depending on the system, that control may involve:
- authorised locksmiths or dealers
- registered system owners
- authorised signatories
- controlled key profiles or blanks
- patents or registered designs
- manufacturer or dealer agreements
- records of keys ordered and issued
Before supplying another key, the locksmith may need to confirm that the requester is authorised or obtain approval from the person responsible for the system.
ASSA ABLOY explains that restricted keys in Australia are generally ordered by authorised people through authorised service centres, with keys cut, recorded and allocated within the system.
A restricted key may open only one door. For example, an apartment key can be restricted even if it does not have master-level access.
For a broader introduction, see what is a restricted key?.
Can a key system be both restricted and master keyed?
Yes. Many commercial, apartment and institutional systems combine both features.
Consider an apartment building:
- resident keys open particular apartments and common areas
- service keys open designated operational areas
- management keys open a broader group of locks
- additional keys can only be ordered through an authorised process
The different access levels form the master key hierarchy.
The controls over ordering and issuing additional keys make the system restricted.
Some Australian products are expressly designed to provide both. For example, dormakaba’s IP9 is described as a restricted key system with secure master-keying capability.
Restricted keys and master keys compared
| Question | Master key system | Restricted key system |
|---|---|---|
| What does it control? | Which locks each key is authorised to open | Who may obtain additional keys |
| Does it create access levels? | Yes | Not necessarily |
| Does it control the authorised supply of additional keys? | Not by itself | Yes |
| Does it usually require an approval process? | Not by definition | Commonly |
| Can it be combined with the other system type? | Yes | Yes |
Is every master key restricted?
No.
A master key system can use a restricted or unrestricted key profile. Master keying describes the access hierarchy, while restriction describes control over additional key supply.
This is important when comparing quotes. A proposal that mentions a master key system should also explain:
- whether the proposed key profile is restricted
- how that restriction is maintained
- who may order additional keys
- who can approve requests
- which locksmith or supplier can produce the keys
- how issued keys will be recorded
Is every restricted key a master key?
No.
A restricted key may be an ordinary user key within a controlled system. It might open one apartment, office, storeroom or other assigned area.
Its restricted status relates to how another key can be obtained, not how many locks it opens.
Why the difference matters when choosing a system
A well-designed master key hierarchy controls where people can go.
A well-managed restricted key process controls how additional keys enter circulation.
Using both can help a building or site maintain better control over access. The physical system defines which doors each key operates, while the ordering process records who requested, approved and received additional keys.
When reviewing a proposal, ask the locksmith:
- Is the proposed system restricted as well as master keyed?
- What protects or controls the key profile?
- Does that protection have an expiry date?
- Who will be recorded as the system owner?
- Who can approve additional keys?
- How will future orders and approvals be handled?
- How will issued keys be recorded?
- What happens if the system becomes obsolete or needs to be expanded?
The ongoing ordering process should be considered alongside the hardware and access hierarchy. See choosing a restricted key system for a more detailed checklist.
If you need another restricted or master-system key
Start by identifying the building or site, the key markings and the locksmith responsible for the system.
Having the physical key does not necessarily provide authority to order another one. The locksmith may need approval from the system owner, building manager, owners corporation manager, property manager or another authorised signatory.
See how to order a restricted key and why restricted keys need approval for the next steps.