Door locks for entrance doors: types and locking systems for maximum security

How is a door lock made? Components and operation

The security level of a door largely depends on what cannot be seen: the lock and the inside components. Every part of an external door is designed to ensure smooth operation and to protect against break-in attempts.

1. Lock cylinder (or barrel): the “heart” of door locks, where the key is inserted. Today, the European standard is the most widely used among cylinders, appreciated for its high level of security and ease of replacement. Inside it are:

• Rotor: the moving part that turns only when the correct key is inserted.
• Pins: small spring-loaded elements that align according to the key profile, allowing the rotor to rotate.
• Door cam: the element that turns together with the key and activates the internal lock key mechanism.

2. Lock case: the metal body recessed into the entrance door, which houses the entire door locking systems. Inside it are:

• Door latch: the spring-loaded element with a beveled edge that keeps the door closed without turning the key and retracts when the handle is pressed.
• Door bolts: steel bolts that extend when the key is turned and secure locks for external doors; in security locks they are usually multiple.
• Backset: a measurement indicating the distance between the door edge and the center of the cylinder, essential when you need to replace a lock.

3. External and fixing components: these complete the locking systems for doors and directly contribute to security:

• Faceplate: the metal plate on the edge of the door from which the latch and bolts extend.
• Strike plate: the plate fixed to the frame that receives the latch and bolts when the door is closed.
• Defender: a hardened steel lock cover that protects the cylinder from the outside, essential against drilling, pulling and snapping.
• Handle spindle: the square bar connecting the handles and operating the latch.

When the key is inserted into the cylinder, the internal pins align, allowing the rotor to turn. This movement activates the door cam, which in turn drives the bolts inside the lock case.

• With the door closed but not locked, the latch keeps the leaf in place.
• Turning the key causes the bolts to slide out and engage the strike plate.
• In security lock solutions for doors, the movement is multiple and synchronized, distributing the closing force and increasing resistance to forced entry.

Door locking systems: types of locks and keys

Door locks for external doors are not all the same. Beyond the basic distinction between key-operated locks and keyless ones, there are many variants that differ in internal structure, security level, opening technology and intended use.

Key-operated locks for doors: main types and differences

Traditional key-operated locks remain the most common choice for entrance doos. They differ according to the cylinder, the locking mechanism and the available security features.

• European cylinder locks: the current standard for modern doors. The cylinder is easy to replace and compatible with many door closing systems. These solutions can be combined with security keys and additional anti-break-in mechanisms.
• Double-bit locks: historically used on armoured doors, they are now less common in new installations. They use a long, toothed key that operates an internal lever mechanism, effective for locking but potentially less secure by today’s standards.
• Cylinder locks with defender: not a different type, but an advanced security configuration. The cylinder is protected by a hardened steel cover that shields it from common break-in attempts such as drilling, pulling or snapping.
• Multipoint locks: these systems feature multiple locking points distributed along the height of the door. When the key is turned the bolts engage simultaneously, anchoring the door leaf to the frame at several points, increasing resistance to forced entry.

Keyless locks for doors: electric and smart options

Keyless locks represent the evolution of traditional locking systems, offering greater comfort and security, access control and integration with modern technologies.

• Electronic door locks: they operate via keypad, badge or card, with access granted by entering a code or presenting an authorized device.
• Door locks with code: access is obtained by entering a numeric combination. They are widely used in modern residential settings, offices and hospitality environments.
• Biometric door locks: these locks open through fingerprint recognition, providing a high level of security because access is linked to personal identity.
• Smart door locks: connected to smartphones or automation systems via apps, Wi-Fi or Bluetooth, they allow remote control and management of access and openings.
• Electromechanical door locks: they combine an electric opening system with traditional mechanical parts, usually including a physical key for emergency use.

Security locks: the 5 most advanced anti-break-in solutions

When it comes to security door locks, the main objective is resistance to forced entry. Modern solutions rely on a combination of features that make break-in attempts more difficult, noisy and time-consuming, increasing the overall level of protection.

1. RC3-certified multipoint lock with European cylinder: this is the highest traditional standard for entrance doors and armoured doors. It combines multipoint locking with a high-security European cylinder resistant to bumping, picking and drilling, together with a hardened steel protective cover. It is the ideal choice in high-risk contexts.

2. Multipoint electromechanical lock with automatic locking: this solution combines traditional mechanics with electronic technology. It enables automatic closing of the door bolts and electronic access management, often including an emergency key. It eliminates the risk of leaving the door unlocked and is highly effective for security.

3. Multipoint biometric lock: access is granted via fingerprint recognition for one or more authorized users, with non-transferable access and no keys to manage. Multiple locking points are activated simultaneously, making it one of the most advanced and secure locks, particularly appreciated in modern and smart living homes.

4. Smart lock with digital access control: this type of lock allows opening via smartphone, code or badge. More advanced models offer notifications, remote control and integration with home automation systems. Security is very high, especially when combined with multipoint locking systems and certified components.

5. European cylinder lock with anti-pull defender: the best classic solution. Even without digital technology, it remains extremely reliable when fitted with protected lock cylinders and anti-manipulation systems. Less secure than the most sophisticated multipoint locks, it offers a much higher level of protection than traditional door locks.

Choosing an entrance door lock: frequently asked questions

Choosing a new lock can raise questions about security and maintenance. Here are some of the most common answers about entrance door locks, to help you understand which solutions are the most secure and how to identify the locking system installed on your door.

What is the best security lock for a door?

The best solution for a home is a multipoint front door lock with a European cylinder, fitted with an anti-pull defender and certified to anti-break-in standards (RC class). This configuration provides multiple locking points along the door leaf, resistance to common forced-entry techniques and greater stability between the door and the frame.

Is it possible to change only the lock on a door?

Yes, in most cases it is possible to change just the door lock or one of its components. The most common operations are replacing the cylinder (often recommended after theft, lost keys or a change of occupants) or replacing the entire lock, especially when upgrading to more secure locks or more modern door locking systems.

Why is it not recommended to leave the keys in the lock?

Leaving keys inserted in the lock on the inside can cause several issues. In an emergency, it may prevent opening the door from the outside with a second key, and over time some cylinders may suffer mechanical damage. In addition, it can facilitate some forced-entry attempts if the cylinder is not designed to manage keys inserted on both sides.

How can you identify the type of lock installed on your home door?

To recognize the type of lock, it is useful to observe a few details: the shape of the key (short and contoured for European cylinders or long and toothed for double-bit locks), the presence of a protective cover, the number of turns when operating the key (multiple ones often indicate a multipoint system), and the edge of the door, where the faceplate can reveal information about the internal locking system.

DQG: entrance doors with integrated security locks

DQG entrance doors are designed to offer protection, comfort and maximum freedom of choice, combining Italian design with high manufacturing quality. All our exterior doors can be fitted with high-performance door locks and advanced locking systems:

• Multipoint locks, which improve the stability and resistance of the external door;
• Automatic locks with multiple latches, which activate locking without using keys;
• High-quality European cylinders, compatible with anti-pull defenders;
• Security levels certifiable up to RC3, on request.

Alongside traditional solutions, DQG also offers advanced keyless locking systems: electromechanical or full smart locks managed via code, smartphone, fingerprint recognition or other devices, with a physical emergency key when required.

Every DQG entrance door is fully customizable: from the lock and security level to the choice of uPVC oru PVC/aluminium profiles, finishes and accessories. To learn more and configure the entrance door best suited to your needs, contact our sales team.