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What is OSDP (Open Supervised Device Protocol)?

Chances are you've already heard about the emergence of OSDP (or Open Supervised Device Protocol), but you may be wondering what all the hype is about. In this article, we give you an overview on Wiegand technology and explain how OSDP works in comparison to Wiegand. We'll discuss the benefits, outline why OSDP is a better option than Wiegand to protect a site, and settle the OSDP vs Wiegand debate once and for all.

Important: This article focuses on the benefits of OSDP over Wiegand. We continue to recommend ICT's proprietary RS-485 protocol as the AES-256 encryption it provides is more secure than the AES-128 encryption of OSDP. However when compatibility with other systems is required, OSDP now gives you a secure alternative.

Overview and History

Many businesses around the world have been relying on technology to secure their premises that hasn't changed for almost 40 years.

In 1975, German born scientist John R Wiegand discovered the Wiegand effect and patented the technology. His specially treated wires produced magnetic fields which were used to create a card and reader that could talk to each other. This became one of the earliest technologies to emerge in modern access control.

Wiegand technology was state of the art when introduced in the ’80s, but it’s unencrypted and unsecured and has since been shown to have massive security flaws against today’s modern security demands. It is susceptible to both man in the middle and replay attacks, leaving your access control open and vulnerable. You can attack a site with cheap, easily obtainable equipment, and there are plenty of demonstrations online showing this can be achieved in seconds.

There was also much confusion among people with only basic knowledge of access control and security as the name ‘Wiegand’ was applied to three different areas of technology: cards and readers, the hardware interface, and the binary data format.

Development of OSDP

In response to Wiegand’s failings, the development of OSDP brought secure communications between devices to access control. The SIA (Security Industry Association) has since adopted and driven the OSDP technology. In May 2020 the protocol became an internationally recognized IEC standard, and OSDP v2.2, which is based on this standard, was released in December 2020.

OSDP is an open-source protocol that aims to improve interoperability among access control and security products. Compared to Wiegand, OSDP also adds encryption, much higher levels of security, plus a lot more functionality and futureproofing. However, even in 2019, 84% of integrators still used Wiegand over OSDP.

Benefits of OSDP

OSDP has many benefits for both integrators and end-users when compared to Wiegand, including: 

Increased Security

Increased Security

OSDP uses RS-485 protocols for secure channel communication with AES-128 encryption. This means you could pair an OSDP reader with a MIFARE DESFire card and an ICT Protege controller to create a totally encrypted communications path from the card to the server.

More Communication

Improved Communication

With Wiegand, data transmission is one-way only, meaning the controller is unable to ‘talk’ to the reader – it can only listen. OSDP allows bi-directional (or full-duplex) communication. Communication is also constant, which means that any interference with the reader cabling will be detected in seconds.

Cheaper To Install

More Cost Effective To Install

OSDP only requires 2 wires to transfer data, saving you time and enabling multi-drop installations. Using a twisted pair cable for data transmission also allows for 6x the wiring length versus Wiegand, so you can safely run a cable up to 900 meters (about 3000 feet) instead of 150 meters (500 feet).

Improved Operability

Improved Interoperability

Being an open-source protocol, OSDP means readers and access control panels can now talk to products from different manufacturers.

If you are not already convinced about why OSDP is better than Wiegand, then imagine what this could mean. The interoperability of OSDP makes it easy to team up ICT's tSec Readers with an existing access control system, or to use third-party OSDP card readers with your Protege system. Add increased security to the time and labor costs saved at installation and there is no contest.

If you want a non technical comparison of how OSDP stacks up against Wiegand, think of Wiegand as a bit like throwing a big party and using your partner’s cousin Bill as the bouncer. He stops most people at the front door, but he’s easily fooled. Show any type of fake ID and Bill will just say “come on in!” By comparison, OSDP is like stationing 2 armed guards at the front door of the party. Not only do they accompany you from your car to the door, they use a secure satellite uplink to check your date of birth and ensure your ID is legitimate. And watch out if the ID is fake or you’re not supposed to be there - they won’t back down.

Implementing OSDP with ICT products

Protege controllers and reader expanders support connection to third-party readers using OSDP. You can also configure certain tSec Readers to communicate with an existing access control system via OSDP, which when combined with ICT mobile credentials also enables secure door unlocking using your smartphone.

For more information on implementing OSDP with ICT products, refer to the following application notes: 

  • AN-254: Configuring OSDP Readers in Protege
  • AN-321: Configuring tSec Multi-Technology Card Readers for OSDP Communication 

You can also watch as Regional Sales Manager Shaun Gardner takes you through OSDP.

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