The 17 Different Types of Keys and their Uses

We use keys every day, but have you ever stopped to think about how many different types there are? Fret not! The article will tell you about the various types of keys and their uses.

Keys are one of the most interesting things manufactured by humankind. They have been around for centuries, and it's fascinating how this mechanism still prevails. However, there have been many advancements in key technology, and there are now dozens of different key types.

From locking up our homes to starting our car engines, keys are essential tools used for various purposes. After all, keys keep our homes, businesses, and personal belongings safe. While we often take keys for granted, it's important to know about the different types of keys and their uses.

This article will answer your curiosity about keys. Before we get into the different types of keys, let's take a brief history lesson about our little toothed guy, the key.

A Brief History of Keys

Keys have a long and exciting history dating back to ancient times. It dates back to around 6,000 years at the same time as locks were invented.

Earliest signs:

The oldest key known was found in the ruins of Nineveh, which was the capital of ancient Assyria. At the time, the keys were made of wood and were bulky and heavy. It was used by inserting the tooth-shaped key in the small opening near the bolts and lifting the hidden small pins. However, the major limitation of this design was that both the key and lock were made of wood. So, they were useless against brute strength or a heavy blow.

Egyptian and Roman touches:

The design was adopted and further improved by the Egyptians. They swapped wood for brass and increased the number of pins in the lock. This pin lock then made its way to Greece and the Roman Empire. The Roman inventors and engineers significantly improved the Egyptian wooden locks. They improved the design by using iron and bronze, making them stronger and more challenging to break.

The Romans were also the first to incorporate keys that had wards, obstructions in the keyhole that prevent the wrong key from being inserted. This is still a common security measure used in many locks today. The Romans also transformed the bulky keys into the Skeleton keys. These keys had a cylindrical shaft with one rectangular tooth. The design of the keys and locks then remained relatively unchanged for centuries until the 17th century.

Introduction of Flat keys:

After that, the major up-gradation of the lock mechanism was made in the 17th century when Robert Barron patented the double-acting tumbler lock.

Around the mid-1800s, Linus Yake, Sr, and his son introduced the modern flat keys. With the use of tumbler locks, the security level of the locks increased, and it became more difficult to pick them. They were easy to develop, and with the easy cutting machine, it was easier to replicate in large numbers. These keys became an instant hit, and it is still being used in our homes and offices.

There are different types of keys made from other materials such as brass, nickel, silver, and even plastic in the contemporary world. The most common type of keys that we use daily is the flat keys, first introduced in the 1800s.

Now that we've taken a quick walk through the critical history let's explore the different types of keys.

Different Types of Keys

As we mentioned before, there are dozens of different types of keys. This segment will explore the 17 different types of keys and their properties.

Transponder Key

A transponder key is one of the most popular key types with a chip embedded in it. As a result, they are often referred to as "chip keys" and are common in newer cars and trucks. This chip sends a signal to the car's computer system, allowing the vehicle to start. If the code doesn't match up, the car won't start. The keys offer you a solid security system and make it nearly impossible to steal your car. A thief would not only have to get the physical key, but they would also need the transponder code.

Transponder keys are also complicated to duplicate. It requires access to the car's database and information about the code. It's difficult for a regular locksmith, but they can easily program a new key if you consult a dealership. One possible downside is that they require battery power, so if the key's battery dies, then you won't be able to start your car. The transponder keys are comparatively more expensive but are worth the benefits you get.

Laser Cut Car Key

The name gives it away that these keys are cut with a laser. Laser-cut keys are categorized by their square or blunt edges on the blade part of the key. Commonly known as "sidewinder keys" or "internal cut keys," they have ridges and patterns cut into the key on both sides. So, you can insert this key into the car's ignition regardless of how it is facing.

They might appear similar to mechanically cut keys but are more accurate and complex. The precision makes them challenging to duplicate, and it requires special equipment.

This creates a more secure system for your car, and it is also challenging to pick. The locksmiths must use internal machinery to cut the key on both sides. Getting this key will enhance the security of your car.

Dimple Key

You might be familiar with the traditional flat keys that we use daily. But a dimple key is quite different from those keys. These unique keys are easily recognizable because of the dimples along the key's blade. The dimples are cone-shaped, and they are cut at different depths. Upon inserting the key into the lock, the pins align with the dimples and allow the blade to turn, opening the lock.

The fact that dimple keys are identical on both sides makes it convenient. It means the key would work regardless of how you insert it into the lock. This allows you to easily open the lock without worrying about the orientation of the key. Moreover, it is more difficult to pick because of its unique design. The dimple keys are used to provide an added security feature against intruders.

Valet Keys

A valet key is a type of key that limits the functions performed with the key. For instance, a valet key may allow you to open the doors and start the ignition, but it won't allow you to access the trunk or glove compartment. They are programmed with special coding to prevent access to certain areas of the car.

The primary purpose of a valet key is to give someone else access to your car without giving them full access to your vehicle. For instance, you may provide your valet key to a parking attendant or a car wash service. This way, you can be assured that they won't have access to your belongings. Valet keys work like regular keys, but the idea is to have an extra level of security as they have some restrictions.

Keycard Key

A keycard key is a key that uses a card instead of a traditional metal key. The card is usually made of plastic and is similar to the shape and size of a credit card. A keycard key has a magnetic stripe or barcode encoded with information. Simply insert it into the reader to use the key, and the door will unlock. Keycards are also more difficult to lose as you can keep them in your wallet.

These keys are electronically programmed to enable them to open specific doors. Your most common encounter with this type of key would be in hotels where you use it to open your hotel room door. They can be easily programmed to allow access to multiple people or cancel it. Compared to traditional keys, keycard keys offer an efficient and secure locking system.

Tubular Key

Tubular keys are another unique key that you might not be familiar with. They have a unique appearance and are named so because of their tubular shape. Also known as "barrel keys," they have a hollowed-out barrel with pins sticking out of the center. When you insert it into the lock, the pins line up with the shear line and allow the plug to turn, opening the lock.

Tubular keys offer a higher level of security as they are more challenging to pick. They are also more durable as the pins are less likely to bend. The chances of correctly replicating a tabular key are meager, so you can be sure that your belongings are well-protected. You can find these keys being used in vending machines, mailboxes, bicycle locks, and some high-security areas.

Primary Key

A primary key is the most essential type of key as it is responsible for opening the door to your home. It is also known as the "master key." The primary key is usually given to the owner of the house or the person in charge of the property. There can be specific locks to different areas or rooms, but the primary key will allow you to unlock them all.

A primary key is ideal for businesses and other commercial properties. The employees can have separate keys for their respective cabins in an office. However, the primary key would still have access to them all. This would enable the security personnel to have full access to the premises in an emergency. Plus, they won't have to bother about having a bunch of keys with you all the time. Since this key can unlock all the doors, keeping it safe and secure is essential.

Paracentric Key

Paracentric keys are exclusive to Paracentric locks and are incredibly uncommon in everyday life. The only place you will find one of these is the prison. They are categorized by their unusual shape, with the tiny teeth lined in addition to a contorted blade. The unique design of the key makes it difficult to duplicate, and the locks are incredibly, extremely hard to pick.

They are primarily used in prisons based on the widespread belief that they can't be picked. For the most part, it stands firm; however, some people have developed ways to pick these without using the key. Well, the chances of it happening are very low but not impossible. Nevertheless, Paracentric keys are considered one of the most secure types of keys.

Abloy Key

The key type is unknown to most locations but is relatively popular in Europe. In fact, it is used as a standard locking system for almost all the homes in Finland. These keys have a unique design that is different from all the other keys on this list. They work by rotating discs enclosed in the key, and the lock is released once they are aligned correctly.

Abloy keys are used on tumbler locks that do not have springs, making them incredibly difficult to pick. Plus, the unique shape makes them hard to duplicate as well. They are a safe pick if you want a high-security locking system for your home.

Skeleton Key

The Skeleton key is one of the oldest types of keys that are still in use today. They get their name from their unique appearance as they have a hollowed-out center with teeth on the outside. These keys are called "passkeys," as they can open several locks. They are often referred to as primary keys, but these keys are only used with warded locks.

The teeth on the skeleton key are responsible for opening the pin tumbler lock by fitting into the wards. Once the key is inserted, the wards are lifted, and the plug can rotate, opening the lock. While they are convenient, the skeleton key is not the most secure type of key. They are easy to pick, which caused a decline in popularity, and they are no longer in use. However, you can find them in old homes and buildings.

Cruciform Key

Cruciform keys get their name from their cross-shaped design and are a fascinating shape. Also called the "cross key," they are commonly used in industrial settings where a reliable locking system is required. They have four flat sides with three sets of teeth sitting at 90-degree angles to each other. The teeth come in different patterns, and the locks can only be opened with a key with the same configuration.

These keys are very efficient, robust, and have a compact design to use in various situations. The cruciform keys are notoriously difficult to pick and are very reliable. However, they are not the most secure as they can be duplicated easily. Still, they offer a high level of security and are commonly used. They are primarily used in industries, but you can get one of these keys for your home.

Magnetic Key

The Magnetic key is a particular type of key that uses magnets to open the lock. These keys and lock systems are becoming increasingly popular as they offer a high level of security. The locking system consists of a series of magnets arranged in a specific pattern. The key has corresponding magnets that align with the ones in the lock, opening it. The key can be used on various locks, such as cylinder locks, deadbolts, and lever locks.

This is a passive locking system that does not use any kind of electronics to function. Magnetic keys are difficult to pick as the tumblers do not move with physical force. You can get a high-security locking system by combining magnets with different strengths and aligning them at different polarities. This will provide a wide assortment of combinations for each key, offering extra security.

Double or Four-Sided Key

The Double or Four-Sided key is, as the name suggests, a key that has two or four sides. They are inserted into the lock in a specific way and are turned to open it. These are the most common type of keys and are used in various settings. The double-sided key is the most basic type used in entry doors, garages, and cabinets. The four-sided key is a bit more complex. It is used in higher security settings such as businesses and government buildings.

If you want better security, then opt for the four-sided variant. They are more secure and sturdy, hence less prone to snap if it gets stuck in the lock. Switching to this lock system is efficient and inexpensive as these are not very expensive. You will be able to improve your home security system without breaking your bank.

Mechanically Cut Key

Mechanically cut keys are the most common and oldest types of keys. They are cut by a machine and are cut to precision. This ensures that the teeth of the key match the corresponding cuts on the lock, allowing it to open. These keys are made with die-cast or mechanical cutting machines that are very basic. Moreover, they have lines and ridges only on one side of the key, making it easy to duplicate.

Mechanically cut keys can be copied easily and made to fit in any type of lock. They are also straightforward to pick as the pins can be moved with little effort. They are most commonly found in old car models or doors of houses. If you have this type of key, be extra careful not to lose it. Moreover, if you want to improve your home security, it is best to switch to a better essential type.

Smart Car Key

These are similar to the transponder keys we discussed above, and they also operate similarly. The microchips in a smart car key send radio signals received by the antennas fitted inside the car. The smart keys allow you to start the car without inserting the key into the car's ignition. You can press a button instead, and the vehicle will start. However, this only works if you are sitting inside the car; you cannot start it from outside of the car.

They can also lock and unlock the car doors, which offers a great deal of convenience. Smart car keys provide high-level security as they are challenging to duplicate. If you lose them, you will have to consult your dealership as the local locksmith won't be able to make a duplicate.

VAT Keys

VAT stands for Vehicle Anti-Theft, and its purpose is to upgrade the safety and security system of your car. It provides additional safety measures that make your vehicle less vulnerable to theft. Essentially, VAT keys have microchips that send a radio signal to the car's computer. The car will only start after receiving the correct signal from the key.

VAT keys are costly and difficult to duplicate or replace. They are slowly becoming the standard in the automotive industry as they offer better security than the other types of keys. If you have a VAT key, you can be sure that your car is well-protected against theft. Lastly, they will only be problematic if you happen to lose them.

Sidebar keys

You must have encountered this type as sidebar keys are most commonly used in safes or vaults. What differentiates this type is that they don't have finger pins and can't go into the keyway both ways. They have a specific sidebar and can only be inserted and turned one way. This makes it impossible for a Sidebar key to go into the wrong lock.

Sidebar keys work with cylinder-based locks that restrict the rotation until the correct key is inserted. They are reasonably secure and serve their purpose of keeping the safes or vaults secure. However, they only have ridges on one side, making it easy to duplicate or pick them.

Uses of Keys

As you can see, there are various types of keys available, each with its advantages and disadvantages. Now that we know about the different types of keys, let's take a look at the various uses of keys:


The security of your home is of utmost importance, and you need to be very careful about the type of key you use. Generally, people don't put a lot of thought into the type of key they use for their homes and use a very insecure type. This can be extremely dangerous as it makes your home vulnerable to burglary.

You don't want someone breaking into your home in your absence, right? That is why it is important to use a security key for your home. There are various types of keys that can be used for your home, and each style has its advantages and disadvantages. You need to choose the right kind of key depending on your needs and requirements.


After the house, we spend most of the time at the office, and it is important to have a secure office space. Like your home, you need to be careful about the type of key you use for your office. You have various options; however, you need to consider the security level you need for your office. The choice also depends on the size of the building and the number of people.

If you have an elaborate office premise with many people, Keycard keys can be your ideal solution. This electronically operated locking system is highly efficient and convenient. The use of the Primary key can also be considered if you want to keep the access authority. Moreover, it will save you from keeping a mountain of keys with you.


Cars are one of the most important assets we have, and it is crucial to keep them safe. If you have one of the older car models with mechanically cut keys, you know they are not very safe. You surely want to protect your car from theft, and the best way is to get a secure lock system (and alarm). Among the various types, the latest smart options are your best bet.

Smart car keys, VAT keys, and transponder keys are some of the best options to keep your car safe. These keys are technologically advanced and offer better security than traditional keys. Moreover, these are difficult to duplicate, so you don't have to worry about someone making a copy of your key.


Keys are not just used for doors, but they are also used for locks. Padlocks are one of the most common types of locks, and they come in different sizes and shapes. The keys for these locks also vary, and you need to choose the right type depending on your needs. They are easily recognizable because of their small size and portability. You also get tiny padlocks for diaries, which come with a key. However, padlocks can easily be picked or broken, so they are not the most secure option.


Safes are storage units used to keep valuable items safe and secure. The type of key used also varies depending on the size and security level of the safe. You can find them in hotels, offices, or banks. People also keep them hidden in secret locations to keep their jewelry or money safe. They are secured with either keys or pre-programmed code. It's difficult to pick these safes, and they offer a high level of security. You can get one depending on your requirement and need for security.

Posted by Pavneet Lobana

Pavneet is a home and lifestyle blogger with a passion for creating beautiful and functional spaces. A self-taught chef, she also loves to cook and share her recipes with others. Whether you're looking to create a cozy reading nook or upgrade your kitchen, she has advice that will help you get the most out of your space.