What is Open Supervised Device Protocol (OSDP)?

Open Supervised Device Protocol (OSDP) is an access control systems standard developed by the Security Industry Association (SIA). The protocol works across all parts of an access control system, including the tag reader, access control panel, and lock.  

The aim of OSDP is simple: to improve the implementation, monitoring, and maintenance of access control systems and their various components. So far, the protocol has done just that—and access control system manufacturers have embraced the use of OSDP. 

But why should you care about the benefits of OSDP? 

Older access control interfaces are outdated and hackable.  

Security technology is constantly changing, and for a good reason. Security systems exist to keep people out. But there are always people who try to hack into these systems. And over time, they expose vulnerabilities, meaning companies need to create new, more secure systems.

The Wiegand interface is one of the systems the security industry now considers vulnerable. The Wiegand interface is a wiring standard used for connecting access control devices, such as card readers and fingerprint scanners, back to the control panel. Devices equipped with the Wiegand interface became popular in the 1980s, and it remained the go-to standard for decades. 

But the Wiegand interface is based on 50-year-old technology, making it outdated today. Wiegand is a point-to-point system: the card reader transmits data directly to the access control panel. The card reader cannot transmit data in any other direction or to any other device. In addition, there is no encryption on the data transferred from the card reader to the control panel. 

Why is the Wiegand interface inferior to newer protocols?

• Wiegand access cards and card readers are simpler and less secure than modern cards and readers. Each Wiegand access card has a fixed ID number that does not change, meaning card duplication is always possible.
• Wiegand devices are “unsupervised.” This means that the devices themselves cannot notify the system owner should the device become compromised. Modern access control devices have this functionality. 
• Wiegand devices must be installed close to the access control panel due to wiring constraints, limiting system flexibility. 
• Wiegand devices cannot receive firmware updates. 

These issues spell major trouble for Weigand-equipped devices. For example, all it took for one security journalist to hack into a Wiegand card reader was a screwdriver and a single microcontroller. And just like that, the journalist bypassed a door without authorization. 

OSDP is more secure and feature-rich than access control protocols of the past. 

Security is at the core of OSDP access control protocol—as it should be! Modern access control systems and devices equipped with OSDP are much, much more difficult to hack. But not only that, OSDP-based systems are flexible and easy to use. 

OSDP comes in two configurations: point-to-point, like Wiegand, and multi-drop. At a basic level, point-to-point OSDP systems work in the same way as Wiegand systems. However, data transmission is encrypted, and OSDP provides for two-way communication. Multi-drop OSDP systems connect all card readers and the control panel to a single communication channel. To put it simply, multi-drop allows for greater flexibility in access control system design and implementation. 

Now let’s look at some key features: 

Security: OSDP uses AES-128, an advanced encryption system, to encrypt and decrypt data. Basically, access control cards pass a secret code to the card reader, which passes that secret code to the access control panel. The access control panel decrypts the secret code, and if it matches the database of authorized users, the door will automatically unlock. Because the data is encrypted, a hacker cannot hijack this transmission and inject code to “spoof” being an authorized user.

Interoperability: OSDP is a standardized protocol, meaning all OSDP-equipped devices work and communicate the same way, much like Z-Wave. This leaves less room for error. Cards, card readers, and access control panels work on the same platform, even as more doors or cards get added to the system. This makes upgrading access control systems with new technology easy. 

Flexibility: One of the biggest advantages of OSDP is that it permits greater system flexibility. Users can install card readers 4,000 feet from the control panel. This is accomplished through RS-845 cables, which use a two-way wiring protocol that enables higher bandwidth data transmissions at increased distances. 

Device Management: Devices equipped with OSDP provide users with updates on the system status. If an error occurs—or worse yet, a card reader or control panel is tampered with—users can quickly fix the problem. And users can also complete regular firmware updates. 

OSDP is a step in the right direction—it is more secure, functional, and feature-rich compared to the Wiegand interface it replaces. As of May 2020, OSDP is the communication standard recognized by the International Electrotechnical Commission. As more security device manufacturers adopt OSDP, commercial consumers will benefit from better security and long- lasting, regularly updated access control systems.

If you are interested in a secure, fully integrated access control system, contact Bay Alarm! Get in touch today and we will be happy to provide a free system quote.