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Blog · 15 February 2023

The different flavours of Mobile Access

Mobile access is a mainstream feature now, and customers ask every vendor for it. But several quite different approaches travel under the one term, which makes it hard to tell what a given service actually provides.

In this article I will describe the various mobile access services we encounter under the same label, focusing on systems that can be used in commercial buildings with different door types. I have categorised them into four groups:

  • Conventional wireless access.
  • Mobile IDs or credentials (virtual access cards).
  • Stand-alone mobile access (offline).
  • Mobile ID and stand-alone mobile access in the same application.

As a starting point, consider the conventional, legacy access control system. Traditional systems use NFC cards (RFID) and key fobs. There are many card technologies available with varying features of security. However, managing cards can be cumbersome, as they need to be physically delivered to the end user. NFC cards and key fobs are therefore not a practical solution for short accesses.

1. Conventional wireless access

In this group the mobile application connects to the cloud service and reports that the user wants to open a particular door. The system then connects to the door to open it, via either wired or wireless access control. We call this group “conventional” because it does not differ much from traditional access control, except that it is connected.

It can be integrated into a reservation system, and into other mobile apps. But the online character has its downside: end users must have good internet connectivity or latency ruins the experience; it does not work offline, which limits its use in remote or underground places; and investment costs can be high, especially for a wired system.

2. Mobile IDs or credentials (virtual access card)

Bitwards Mobile ID belongs to this group. The mobile application acts as a virtual card, mimicking an RFID card’s behaviour. When the end user identifies themselves with the phone, over NFC or BLE, the application communicates with the access control reader. The reader passes the received value over the Wiegand or RS-485 connection to the door terminal or controller. The access control system uses the user’s ID to identify the person and verifies whether their access rights apply at that time. If they do, the controller opens the door.

  • In this model the phone is a virtual credential card.
  • It always requires wired or wireless access control.
  • An access control system typically requires 5–10 minutes to deploy a change in access rights to the door.

It enables retrofitting from RFID-only access control to mobile use, and can be used in parallel with RFID cards. Against that: investment cost for the system can be high, especially when wired, and it is not suited to granting access rights from a reservation system without integration into the access control system.

3. Stand-alone mobile access (offline)

Bitwards Mobile Access belongs to this group. These are cloud services with access control and mobile identity management built in. In most cases the cloud service issues the credentials to the mobile application. When the user opens a door, the application communicates with the lock, providing encrypted data with checksums that the lock uses to decide whether the end user has access rights. The communication uses BLE or NFC and works offline.

The administrator uses the cloud service to manage access rights with door groups and weekly schedules, and the service adapts to include exceptions to the schedule. The differentiator over traditional access control is that the service can issue credentials instantly: the APIs and the offline nature of the system enable fast admittance of access rights over the API, and end users can be sure the door will open once the rights are downloaded to the application. Investment costs are much lower than with conventional systems. The trade-off is that door status cannot be monitored in real time.

4. Mobile ID and stand-alone mobile access in one application

Here stand-alone mobile access is combined with Mobile ID. The Mobile ID service is used where traditional access control exists in parts of the building, typically the entrance doors. Once inside, stand-alone access covers the parts of the building where traditional access control is not implemented. The end user still has one application and a single sign-in — no logging out and in to use different accounts — and reaches every door and access point of the building from it.

  • It enables retrofitting from RFID-only access control to mobile use, while adding new doors at a lower investment cost.
  • It offers modern APIs for integrating new services.
  • It makes use of the existing investment in the door environment.

Five questions to ask about mobile access

  • Do you need conventional access control, or would a lighter, less expensive, more flexible solution serve you without compromising security?
  • Do you have existing access control and want to offer users a mobile app as a key, or do you want a completely new system with mobile access — or a combination of the two?
  • Does the service work as an online service, or is it offline (stand-alone)?
  • Do you need a mobile access system on its own, or are you considering integrating it into a reservation system?
  • How flexible is the system, considering your future plans?

Text: Niklas Kaustinen, CTO and co-founder, Bitwards. Graphics: Bitwards / Susanna Määttä. Originally published on bitwards.fi, 15 February 2023.

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