The KeeLoq® rolling code is a security technology used in radio access control systems, such as remote controls for doors or automated gates. It protects installations against signal duplication and makes systems much safer than those using a fixed code.
Operating principle
In a fixed-code system, the signal transmitted by the remote control remains the same each time it is used. An intruder could record this signal and replay it to gain access to the site, which represents a major security flaw. The KeeLoq® rolling code solves this problem by generating a unique code each time the remote control button is pressed. Each code can only be used once, preventing any attempt to reproduce the signal.
Synchronization between transmitter and receiver
The security of the KeeLoq® rolling code relies on synchronization between the transmitter and the receiver. Both devices share the same cryptographic algorithm and an internal counter. With each use, the transmitter generates a new code based on this algorithm and the counter. The receiver compares the received code with those it can generate on its own.
Even if the remote control has been used out of the receiver’s range, the receiver can recognize future codes generated by the algorithm and grant access. Codes that have already been used are automatically rejected, ensuring that no intercepted signal can be reused. This synchronization guarantees both reliability and security, even in environments with multiple users or unregistered button presses.
Advantages of the KeeLoq® rolling code
Using the KeeLoq® rolling code offers several major benefits for radio access control systems:
• Enhanced protection against intrusions through code capture and reuse.
• Reliable operation even when the remote control is used out of the receiver’s range.
• Compatibility with a wide range of radio transmitters and receivers, offering flexibility for different types of installations.
• A proven technology for securing garage doors, gates, and industrial access points.
The KeeLoq® rolling code remains a benchmark in the field of secure radio systems, providing a high level of security while ensuring simple and reliable use for users.
