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Enhanced Padlock Key Security Options Explained


The Squire Stronghold SS100CS padlock is recognised as the world’s strongest padlock. In this post we look at the exceptional keying options that help make this padlock, and others in the Stronghold range, incredibly secure.

In a previous post we highlighted some of the challenges faced by those responsible for managing collections of padlocks. We explained what the terms ‘keyed to differ’, ‘keyed alike’, ‘master keys’, ‘grand master keys’ and ‘great grand master keys’ meant and we’ve summarised these again at the end of this post.

In this post we are looking at some of the excellent padlock key security options available today.

Padlock Components

Padlocks are comprised of three important components. The shackle, the body and the locking mechanism or cylinder.

The shackle is typically a loop of strong metal that opens up to enable the padlock to be secured around whatever is being locked in place. There are a variety of shackle designs, lengths and diameters so this is an important consideration when buying a padlock. Another important shackle attribute is how strong it is, which is determined by the metal, how it is treated and its diameter.

The padlock body is designed to contain and protect the locking mechanism. These are generally metal and available in a variety of shapes, sizes and styles. Importantly, they are designed to provide protection against attack and ensure the enclosed locking mechanism can`t be tampered with or damaged. 

The locking mechanism enclosed within the padlock body may be key operated or use a combination code, entered via rotary dials or push buttons. There are some padlock designs that operate from both combination codes and keys. Pin-tumbler locks or cylinder locks are discused in more detail below.

Padlock Cylinders

A padlock cylinder, or key cylinder, is the central element of a padlock into which the key is inserted. The cylinder contains a number of lock pins which are shifted into position by the inserted key. If the key is the right one for the lock the pins are aligned and the lock will operate.

High security lock cylinders are also known as barrel locks, profile cylinder locks or pin tumbler locks. Although the basic principle of pin tumbler locks may date back to 2000 BC in Egypt, it wasn’t until 1805 that a double-acting pin tumbler lock was patented in England by American physician Abraham O. Stansbury. The double-action meant that lifting the pins both too much or too little would prevent the lock from opening.

One of the primary advantages of a cylinder lock is that the lock cylinder can be changed without having to change the entire lock hardware. Another major advantage is this type of lock allows lock manufacturers to offer cylinders in various formats to support keyed-alike, keyed to differ and master keyed requirements.

Pin-tumbler locks use a collection of pins, typically 5 or 6. These pins have both an upper or top halves and lower, bottom pins. When a sawtooth key is inserted these pins are pushed to various heights. If the correct key is inserted then the indentations cause the pins to shift such that the line between the upper and lower sections of each pin are aligned, establishing an even shear across all the pins. This allows the lock barrel to be rotated by the key and locked or unlocked. If an incorrect key is inserted the key indentations don’t result in the shear line being equal across all of the pins, preventing the lock from operating.

Dimple Keys & Locks

Traditional pin tumbler lock keys use the key edge to manipulate lock pins. Dimple locks and keys use a variation of this lock design that instead of using the key edge uses the flat side of the key blade as the biting area. This type of lock and key has unique dimple characteristics that make locks very difficult to pick.



squire sawtooth and dimple keys
Squire Sawtooth and Dimple Keys

A notable advantage of dimple keys is the high number of pin positions offer more combinations which makes the probability of encountering a coincidental key match much lower.

squire dimple key options
Squire Dimple Key with Security ID

The following Squire Padlocks are all available from our store with Dimple Keys:

It should be noted that dimple keys are not compatible with the SS100 padlock.

Restricted Keys & Padlocks

One of the main security risks associated with standard key and padlock systems is that anyone can potentially copy these unrestricted keys. In fact many users will pop along to their nearest key cutting service with a key to get some spare copy keys cut.

Restricted keys and locks operate in the same way as standard padlocks but there is a tight restriction imposed on key-cutting and copying. These locks are supplied with unique key security cards which must be produced when replacement or additional keys are requested and these keys can only be provided by authorised suppliers and locksmiths who are able to obtain the required key blanks. If all keys were lost Henry Squire can produce replacements based on the ID recorded on this security card.

An excellent example is the Squire S100 padlock with twin restricted R1 lock cylinders. This is the first padlock to achieve the highest LPCB (Loss Prevention Certification Board) Level SR4 accreditation along with rigorous CEN 6 approval. It`s also worth knowing that the closed shackle padlock was tested to Sold Secure Diamond standard with a 22mm high security chain.

squire ss100 padlock
Squire SS100 Open and Closed Shackle Padlock

This lock features dual lock cylinders which are available as "Standard High Security", "Restricted" or "Protected" type cylinders. The R1 restricted key option, that prevents unauthorised key duplication, is provided as standard on these locks when purchased directly from Insight Security. While the SS100S has two key cylinders that operate from the same key the SS100S/KD has two key cylinders that require separate, distinct keys.

The 6-pin locking systems means there are up to an incredible 530,000 key differs and these padlocks can be supplied in master keyed and keyed alike configurations.

Protected Keys & Padlocks

Protected padlocks and keys take this key duplication security to the next level. Like restricted keys and padlocks, they are supplied with unique security key cards. These guarantee users that copies of their keys can never be cut without their authorisation. The key blanks used are more intricate than those used for restricted keys and they are not made available to locksmiths. So these protected keys can only be produced by the manufacturer, Henry Squire. This provides lifelong, guaranteed key security.

Key Blanks

Key dimensions and keyways (end view) differ, which is why separate keys are required for each type of lock.

Keyway, Cylinder and Key Profile

 Padlock Keying Options

Padlock keying options can be confusing. Here’s a summary explanation of the most common keying options used by our customers. These padlock keying options can be used in combination to fulfil specific lock security management requirements. If you are not sure what you need contact us and we will help.

Keyed to Differ or Keyed Different Padlocks

Keyed to differ or ‘keyed different’ padlocks is the standard keying option for most padlocks. It simply means that each padlock is operated by it`s own key and the number of ‘differs’ is determined by the lock cylinder specifications. The number of pins used by the lock cylinder is one of the primary factors, along with depth spacings. The greater the number of pins the higher the number of ‘key differs’ which means there are fewer locks with the exact same keys.

Keyed Alike Padlocks

Keyed alike padlocks are also known as ‘keyed to pass’. This simply means that all locks in a keyed alike suite of padlocks can be operated from one common key that fits them all. In other words, the key from any of the padlocks in the Keyed Alike suite will operate all the other locks in that suite.

Keyed alike padlock suites are sometimes used for convenience but if a key is ever lost there can be significant security concerns.

Master Keyed Padlocks

A master keyed padlock suite uses a collection of secure ‘keyed to differ’ padlocks along with a special ‘master key’ that can operate them all. These locks include additional design features that enable them to be operated by both the user key and the master key.

master key option
Master Key Suite

Master keyed systems are used in a wide range of environments such as schools and businesses where individual users need a high security locking system while supervisors, managers and security personnel also need to be able to conveniently operate these locks.

Grand Master Keyed and Great Grand Master Keyed Padlocks

Grand master keyed and great grand master keyed padlocks extend the master keyed concept into two further tiers of padlock keying. A grand master keyed system refers to a number of master keyed padlock suites that can be operated by a single grand master key. While each of the master keyed suites has it`s own master key, these are restricted to the padlocks in each suite. While the grand master key will operate them all. And this hierarchy can be extended further to include great grand master keys that can operate all of the padlocks in a grand master keyed collection of master keyed padlock suites.

If you have any questions about padlock security and which options are appropriate for your needs, remember that we are here to help. Give us a call on 01273 475500 and we’ll provide you with free, expert advice.

This message was added on Thursday 9th February 2023

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