What is Keyed Alike? What does Keyed Alike mean?

Keyed Alike simply means that all of the locks can be unlocked using the same key. In a keyed alike system, all of the locks in that system can be opened using the same key. Keyed Alike is often abbreviated as KA, especially when referring to padlocks.

Before we go any further, here are a few definition that will be necessary to your full understanding:

The part of a key that engages with the locking mechanism in a lockable device
Key Bitting refers to how a key needs to be cut in order for it to properly engage with the pins, discs, or wafers in the lock cylinder for the key to function properly and turn the cylinder to disable the locking mechanism and ultimately unlock the lockable device.
A Padlock Bumper, generally constructed of rubberized plastic, sometimes colored, helps protect as a scratch guard so that the padlock does not cause any damage to the surface of what it is physically securing.
Cut Key
A duplicate or replacement key that is cut to match another key, or a specific lock cylinder bitting. Key Cutting can be done using a programmable key cutting machine that recognizes specific key numbers, or key cutting can also be done on a manual key cutting machine by lining up a cut key with a key blank and making an exact copy of the original cut key.
Lock Cylinder
A Lock Cylinder is part of the locking mechanism in a lockable device that engages with a key to unlock the device.
Blade or Disc Tumbler Cylinder
The Blade Tumbler Cylinder or Disc Tumbler Cylinder uses a number of uniquely slotted detainer discs to define the required bitting for a key.
Pin Tumbler Cylinder
The Pin Tumbler Cylinder uses pins and springs to define the necessary bitting for a key.
Tubular Pin Cylinder
The Tubular Pin Cylinder uses similar pins and springs as a Pin Tumbler Cylinder, but the Tubular Pin Cylinder has the pins arranged in the shape of a circle creating the tubular keyway on this cylinder that requires a tubular cut key.
Wafer Tumbler Cylinder
The Wafer Tumbler Cylinder uses flat wafers that will only allow the proper corresponding cut key to enter the cylinder and ultimately unlock the device. It is common for the Wafer Tumbler Cylinder to be mistakenly confused with the Disc Tumbler Cylinder, but make no mistakem they are two completely different locking mechanisms.
Hidden Shackle
A Hidden Shackle Padlock has a fully concealed shackle, on the back side of the padlock, which is literally hidden from view, which makes it impossible to cut.
A Key is a tool with which to unlock a lockable device.
Key Blank
Key Blanks are templates used to match specific keyways and cylinders. A Key Blank is an uncut key that can be cut to match a specific cylinder biting.
Key Number
A Key Number is a number stamped or engraved on a key that identifies the specific bitting of the key and how a key blank will have to be cut to match a specific key number.
A Keyway is a slot on the exterior of a lockable device cylinder that is made to receive a specific key.
A Padlock is a detachable and portable locking device that has the ability to pass through the staple of a hasp, a chain link, ring and etc. by means of a shackle.
When unlocked, a locking device can be rekeyed where the cylinder locking mechanism is manipulated to accept a different key than the one it currently uses. [Please Note: Not All Locks Are Rekeyable]
A U-shaped metal link used to secure things together - Padlock Shackles may not always be U-Shaped as with Hidden Shackle Padlocks and certain other Special Application Padlocks.
Specifically referring to a Shrouded Shackle on a Padlock, this additional bit of padlock material provides a cover that is meant to conceal. A padlock shroud partially covers the shackle to protect from wrap attacks and bolt cutters.

What are the benefits of Keyed Alike?

Because Keyed Alike offers the option to use the same key to open multiple locks, the greatest benefit to be gained with a keyed alike system is the convenience of one key. No longer will you have to deal with key ring bulk like a High School Custodian and search for the correct key at every lock, nor will you have to use cleverly colored key head covers to identify which key goes to which lock; with a keyed alike system, all you will need is the one key to open all of your locks.

Same Key Convenience also eliminates the time wasted searching for keys and allows you to rest easy with the knowledge that all of your physical security devices are doing their job and only allowing your key access.

Another benefit to a keyed alike system is that more locks can be added to your system. You can purchase locks Keyed Alike to your Key Number knowing that the key you already have will work with all of the new locks you are procuring. In certain cases, rekeyable locks and rekeyable padlocks can also be rekeyed to match your existing key that you are using with your keyed alike system.

It's also very easy and inexpensive to or order duplicate and/or replacement keys because you only have the one key number, based on the one key blank to get the one cut key to work with all of the locks in your keyed alike system. Otherwise, you might have to order any number of keys from any number of different key blanks. Honestly, that would be a hassle that no one should have to deal with, especially you.

What is required for Locks and Padlock to be Keyed Alike?

There are a few specific, and simple, requirements that will need to be met in order for your locks and padlocks to be keyed alike and match your key. The Cylinder and the Keyway must be identical. If the Keyway doesn't match, there is no way your key is even going to go into the lock. The Cylinder must not only be the same type of cylinder, but it must also have the same number of Discs, Pins, or Wafers each aligned to match the existing bitting specified by your key number so that your key will be able to function properly in the lock. A Cut Key for a 4-Pin Tumbler Cylinder will not work on a 5-Pin Tumbler Cylinder. Oftentimes key numbers are associated with a specific Cylinder and Keyway, it is always a good idea to ask a Padlock Professional any questions you may have to ensure that you are ordering the proper locks to match your key.

What are the weaknesses of a Keyed Alike Systems?

Before we get to that, let us be clear here that physical security devices are not always foolproof. Their main purpose is to deterring theft, but sometimes, even the strongest lock in the world cannot stop crime. Padlock vulnerability is one of the few times in life where the phrase, "you get what you pay for", is applicable. If you are securing equipment with significant value, do not be a bargain hunter and go cheap with your locks and padlocks. The price of a lock or padlock generally reflects the level of security that it shall provide.

With a Keyed Alike System, Key Holder Responsibility will be the greatest concern. If a key goes missing, that means that there is the real possibility that someone else will have access to all of the locks in your Keyed Alike System. Ultimately, all of the locks in your system will need to be rekeyed or replaced.

What if I have trouble remembering my Key Number?

The Master Lock Company LLC offers a free app that allows you to safety save your passwords, or key numbers. This is a very handy tool for those who are responsible for managing many Keyed Alike Padlock Systems because it will allow you to save the Key Numbers for each of your Keyed Alike Systems. https://www.masterlockvault.com