What is Key and Key Control? Types

  • Post last modified:16 April 2023
  • Reading time:11 mins read
  • Post category:Hotel Management

What is Key and Key Control?

A key is a device that is used to open a lock. A typical key consists of two parts: the blade, which slides into the keyhole to unlock the door, and the bow, which is left protruding so that torque can be applied by the user to open the door. The blade is usually designed to open one specific lock, although master keys are designed to open sets of similar locks.

A system of key control is essential to the security of a lodging property. All keys whether metal or electronic should be adequately controlled. The security of a key lock system is seriously weakened when keys are issued to a great number of people or to anyone who has no legitimate need for a key. The best lock in the world may be unable to protect the property or its guests if poor key control allows a criminal to obtain a key to that lock.

Types of Keys

Most lodging properties use at least three types of keys. These types typically include emergency keys, master keys, and guestroom keys.

Emergency Key

The emergency key opens all guestroom doors, even when they are double locked. It can be used, for example, to enter a room when the guest needs help and is unable to reach or open the door. The emergency key should be highly protected and its use strictly controlled and recorded; it should never leave the property. One procedure for emergency keys is to have them locked in a safe or safe deposit box and signed out by the individual needing one. The log should be dated and signed by the individual taking the key.

Master Key

A master key is designed to open a set of several locks. These locks also have keys that are specific to each one (the change key) and cannot open any of the others in the set. Locks that have master keys have a second set of the mechanism used to open them which is identical to all of the others in the set of locks. For example, master keyed pin tumbler locks will have two shear points at each pin position, one for the change key and one for the master key.

A far more secure (and more expensive) system has two cylinders in each lock, one for the change key and one for the master key. Larger organizations, with more complex “grandmaster key” systems, may have several master key systems where the top-level grandmaster key works in all of the locks in the system.

A master key opens all guestrooms that are not double locked. Depending upon the need, the master key may be further established as a housekeeping staff master key, a floor supervisor master key, and a grand master key for management purposes.

Grand Master KeyKey operates all rooms serviced by a particular room maid or housekeeping staff.
Floor Supervisors Master KeyKey operates all sections on the floor/ floors supervised by the particular supervisor.
Key operates all rooms serviced by a particular room maid or housekeeping staff.Key operates all rooms serviced by particular room maid or housekeeping staff.

Above keys will not open the lock when the Guest has Double Locked it from the inside.

From a security point of view, master keying is undesirable; but from a practical point of view, however, it is necessary. Master keying presents two security drawbacks:

  • First is the danger that if a master key is lost or stolen, several locks in the system would be compromised, thus providing access to all those locks.

  • Second is the loss of the master key.

An answer might be to use non-master key sets for high-security areas and master key sets for low-security areas.

Guest Key

The hotel guest room key is normally issued to open only one room for which it was intended, viz. individualized key for each lock. If the guest room lock is in shut-out mode the guest room key can neither open it nor lock from outside of the room.

Guiding Principles in Key Control System

  • Security of keys is essential from the moment they arrive on site. Keys should be stored separately and securely.

  • No unauthorized person should be allowed access to any key, either to examine or handle it, since a photograph or impression can be taken in a few seconds and a duplicate subsequently made.

  • Keep a logbook of all keys signed out.

  • Establish a protocol for the distribution of keys.

  • Use keys that do not identify the property’s name, address, logo, or room number.

  • Perform an annual key audit

  • When keys are lost or stolen, the locks should be changed or rotated to another part of the property.

  • Authorised employees should remind guests to return keys at check-out.

  • The loss or suspected compromise of a key should be reported immediately and, after due investigation, a decision be made as to whether or not the lock should be changed.

  • Place well-secured key return boxes in the lobby, at exit points of the property, and in courtesy vehicles.

Limitations of Metal Key

  • Metal keys require a hotel to maintain an elaborate key control system with daily inventories of master keys and E-Key checkout logs for the staff.

  • The guest has no way of knowing that an adequate key control system is in place.

  • Metal keys can be easily duplicated. And if a master key is duplicated, the security of the rooms is seriously compromised.

  • If a room key or master key turns up missing, the affected locks must be changed. This incident creates an ongoing maintenance problem and expense for the hotel.


Metal room keys are being replaced by electronically coded key-cards. A keycard, while not actually considered a key, is a plastic card which stores a digital signature that is used with electronic access control locks. It is normally a flat, rectangular piece of plastic and may also serve as an ID card.

There are several popular type of keycards in use and include the mechanical holecard, bar code card, magnetic stripe card, smart card (embedded with a read / write electronic microchip), and RFID proximity cards. The keycard is used by presenting it to a card reader; swiping or inserting of magnetic stripe cards, merely being brought into close proximity to a sensor.

Bar code technology is not a secure form of a key, as the bar code can be copied in a photocopier and often read by the optical reader. Magnetic stripe keycards are becoming increasingly easy to copy, but have the security advantage that one may change the stored key in a magnetic swipe card in case the current key is compromised.

Key-cards have the capability of being randomly coded at the point of registration, which re-emphasizes the guest perception of room security. Key-card control is computer-based and therefore creates the necessary audit trail automatically. Master keys can be changed in a matter of a few keystrokes and lost key-cards are easily removed from the system.

One of the best security features is the ability of the computer to investigate each door lock and get a printout of everyone who accessed a particular room. This dramatically cuts down on theft from the rooms by hotel employees.

The security advantage of the key-cards has made it popular and many medium and large sized hotels are adopting this key-card system.

Article Reference
  • Ellis, Raymond C. and Stipanuk, David M. (1999), Security and Loss Prevention Management, Lansing MI.

  • Joan C. & Lennox, Margaret Branson (1969), Hotel Housekeeping Principles and Practice, Edward Arnold, London.

  • Rosemary Hurst (1971), Housekeeping Management for Hotels and Residential Establishments, William Heinemann.

  • Louis A. Tyska, Lawrence J. Fennelly (2000), Physical Security 150 Things You Should Know, Elsevier.

  • Bill Phillips (2005), The Complete Book of Locks and Locksmithing, McGraw-Hill Professional.

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