Bluetooth Pairing Part 5, Legacy Pairing – Out of Band

Bluetooth Pairing Part 5, Legacy Pairing – Out of Band

In previous blogs, we touched on topics such as Passkey Entry and Numeric Comparison which are two types of pairing methods. Today, I will introduce another one, out of band. The out of band (OOB) association model is designed for scenarios where an out of band mechanism is used to both discover the devices as well as to exchange or transfer cryptographic information which would be used in the pairing process. Out of band is a flexible option for developers that allows you to define some of your... Continue Reading

Exploring Bluetooth 5 - How Fast Can It Be?

Bluetooth 5 is here and it’s a major step up from the current standard for wireless connectivity, Bluetooth v4.2, with its 4-times longer range, 2-times higher speed, plus 8-times larger advertisement packet length for data. Developers can visit the Bluetooth SIG website and download the latest Bluetooth core spec here. Right after Bluetooth 5 was released, a developer asked me, “with the higher bandwidth feature, how fast can Bluetooth 5 be?” Today, we will have an inside look at Bluetooth low... Continue Reading

Bluetooth Pairing Part 4: LE Secure Connetions - Numeric Comparison

Part 3, we had an overview about LE Legacy pairing with passkey. Other than LE Legacy pairing, LE Secure Connections is the other option for pairing. LE Secure Connections is an enhanced security feature introduced in Bluetooth v4.2. It uses a Federal Information Processing Standards (FIPS) compliant algorithm called Elliptic Curve Diffie Hellman (ECDH) for key generation. For LE Secure Connections, it support four association models: Just Works Numeric Comparison (Only for LE Secure Connections) Continue Reading

How to Deploy Bluetooth Secure Gateway on Intel Edison

Bluetooth SIG released an advanced toolkit, the Bluetooth Secure Gateway, last September. With this toolkit, you can learn how to connect your Bluetooth devices to the Internet of Things. The hands-on labs in this kit will help you familiarize yourself with how to set up the popular ARM-based Raspberry Pi2/Pi3 to act as a secure gateway for your Bluetooth low energy devices. I became curious to see if there any other popular dev boards which could run the Bluetooth Secure Gateway aside from one... Continue Reading

Selecting a Bluetooth Microcontroller—a Developer’s Perspective

There are two major branches of Bluetooth application development. One is mobile platform development like smartphones and tablets running on iOS, Android or other mobile operating systems. The other is embedded application development. I often get questions from Bluetooth low energy developers who are curious, “how can I select a suitable Bluetooth LE embedded microcontroller for my prototype or product?” In this blog, I outline some tips for choosing the right one. Module/Chipset Most Bluetooth... Continue Reading

Bluetooth Pairing – Part 3: Low Energy Legacy Pairing, Passkey Entry


In my previous blog on Key Generation Methods,” I talked about Key Generation Methods—if the initiating and responding device meet some IO capability conditions, they choose LE legacy Bluetooth pairing Passkey Entry method.In this blog, I look at legacy pairing with Passkey Entry and how it works.Figure 1: LE Legacy Pairing, Passkey EntryTemporary Key (TK) and Random Number GenerationWhen you use LE legacy pairing, the pairing is performed by each device generating a Temporary Key (TK). If the IO... Continue Reading

Bluetooth Pairing Part 2: Key Generation Methods


In “Bluetooth Pairing Part 1: Pairing Feature Exchange,” we talked about the pairing feature exchange in Bluetooth with low energy. The pairing feature exchange is used to make both devices, initiator and responder, understand each other’s pairing features.The pairing features that can be enabled are: OOB Data Flag bit MITM—Man-In-The-Middle bit SC—LE secure connection indicator bit IO Cap—IO Capabilities*For an introduction to these features, please refer to “Bluetooth Pairing Part 1: Pairing Feature... Continue Reading

Bluetooth Pairing Part 1: Pairing Feature Exchange


In the Bluetooth Core specification, there are three major architectural layers: Controller, Host and Application. In the Host Layer, there is a module called Security Manager (SM) which defines the methods and protocols for pairing and key distribution, the corresponding security toolbox, and the Security Manager Protocol (SMP) which defines the pairing command frame format, frame structure and timeout restriction. The Security Manager (SM) uses a key distribution approach to perform identity and... Continue Reading

Ten Important Differences between Bluetooth BR/EDR and Bluetooth Smart


As you may know, there are two major Bluetooth technologies within the Bluetooth core specification, Bluetooth BR/EDR—Bluetooth Basic Rate/Enhanced Data Rate—and Bluetooth Smart technology. You can find them in the Bluetooth Core Specification, version 4.2, volume 2 and volume 6. As a Bluetooth developer, it is important that you understand the differences of each technology beyond the radio controllers and power consumption.Physical ChannelAll radio communication takes place over some form of defined... Continue Reading