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  • Writer's pictureDalia Zarhin

Everything you NEED to know about Master key systems!

Updated: Jun 11

Master keys are a fundamental component in the security and management systems of many buildings, especially in commercial settings. Here’s a comprehensive overview of everything you need to know about master keys:

What is a master key?

A Master Key System is essentially a sophisticated method of keying locks to allow for multiple levels of access within a building or a set of buildings. Let's delve into it in more detail:

  1. Basic Structure: At its core, a master key system is built around a hierarchical structure of keys. Each key in the system is designed to open one or more specific locks, but there's also a master key that can open all the locks in the system.

  2. Keying Hierarchy: The system is structured in a hierarchical manner. At the lowest level, you have individual keys that can only open specific locks assigned to them. These keys are often referred to as change keys or user keys. Then, there's the master key, which can operate all locks within the system. Additionally, there can be sub-master keys, which can open a subset of locks, but not all.

  3. Access Control: The primary purpose of a master key system is to provide controlled access to different areas within a building or buildings. For instance, in an office building, individual employees might have keys that only open the doors to their own offices, while supervisors might have keys that open all the offices on their floor, and a building manager might have a master key that opens all doors in the building.

  4. Flexibility and Convenience: One of the key advantages of a master key system is its flexibility. It allows for tailored access permissions according to specific needs or roles within an organization. It also offers convenience, as it reduces the number of keys an individual needs to carry while providing access to multiple areas.

  5. Security Considerations: While master key systems offer convenience, they also require careful planning to ensure security. If a master key falls into the wrong hands, it can compromise the security of the entire system. Therefore, proper key management, including key issuance, tracking, and rekeying when necessary, is crucial to maintaining security.

  6. Implementation: Implementing a master key system involves meticulous planning and coordination with a locksmith or security professional. The system needs to be designed based on the specific layout and access requirements of the building or buildings it will be used in.

How Does a Master Key System Work?

In a master key system, locks have pins that are matched to new keys in a way that allows them to be opened by more than one key. The most common configurations include:

  • Master key: This key opens all the locks within the system, though it is typically held by property managers or owners.

  • Sub-master keys: These keys can open all locks within a particular section or group of a building but cannot open all locks like the master key.

  • Individual keys: These keys open only one lock (or one group of locks that are alike). They are usually assigned to individuals who need access to specific areas.

Example for a master key system
Example for a master key system

Benefits of a Master Key System

  1. Controlled Access: Allows precise control over who can access different parts of a building.

  2. Convenience: Reduces the number of keys needed, as one key can open multiple locks.

  3. Enhanced Security: When combined with high-security locks, a master key system can provide a high level of security against unauthorized copying of keys.

  4. Scalability: Easy to expand as your business or building expands.

  5. Cost-effective: More economical and efficient than replacing locks for security or implementing more advanced and expensive access control system.

Installation Considerations

Implementing a master key system requires careful planning and precision. It’s crucial to determine which doors each person or group should have access to and to keep the system updated as staffing or business needs change.

Security Risks

While master key systems offer great convenience, they also pose risks if not managed correctly. The loss of a master key can compromise the entire system. To mitigate this risk, it’s advisable to use patented keys that cannot be duplicated without proper authorization, and to use electronic access control systems alongside mechanical keys where possible.


Regular maintenance is required to ensure that the master key system works reliably. This includes regular checks and repairs, updating the system to cover any security breaches, and rekeying locks as needed to maintain security integrity.

Choosing the Right System and Locks

Selecting the right type of locks and designing an appropriate key system is critical. It’s essential to work with a reputable locksmith or security professional who has experience with master key systems. They can provide valuable insights into the type of system that would best suit your needs, taking into account the size of your facility, the number of users, and your security requirements.


Master key systems can dramatically improve the operational efficiency and security of a building or facility, but they require thoughtful management to maximize their benefits while minimizing risks.

We at Aegis Locksmith Services are here to answered any question or request.

Don't hesitate to contact us 470-756-0417 or at

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