connecting, bonding, pairing, and whitelists

[GlennEngel]

I'm a bit confused about nomenclature and am looking for guidance in how best to implement the needs of my ble app. From the S110 perspective, how are connecting, bonding, pairing, and whitelists related? What do these terms mean in relation to the device_manager?

For my application I can currently discover and connect from android and read and write characteristics. At this point I would like my ble device to only allow connections from the last successful connection until a reset procedure is initiated via a button press. I've read about irks and addresses and it really sounds like using a library is the way to go. I'm not concerned with security and passkeys for my application but wonder if I should be or if there is any downside. There is no visible ui on my ble device other than an led.

What is the most straight forward means of providing the connection storage, connection denial, and reset back to 'open'?

[Einar Thorsrud]

This is a short description of the terms, and how they are linked together:

• Connection: A central (master) can connect to a peripheral (slave). While the connection is active the master and slave will communicate regularly at a determined interval. This connection interval can be between 7.5 ms and 4 s.

• Pairing: Devices that are initially connected can exchange encryption keys and encrypt the link. When they have, the link is secure and they are paired.

• Bonding: Paired devices can be bonded. This means that they store the keys that have already been exchanged when they paired and use those again the next time they connect.

• Whitelisting: The whitelist is used to restrict connection or scanning from any other than predetermined (known) devices.

The SDK provides libraries in order to assist in bonding and whitelisting: The older device manager and the new (currently experimental) peer manager. You can reset all the bonding information and disable the whitelist when desierd. E.g. with the peer manager you can delete all bonds with pm_peer_delete_all() and create a new empty whitelist (pm_wlist_create())and set it (pm_wlist_set()).

[Einar Thorsrud]

You are right. Most phone (at least iOS devices and for Android devices with Lollipop or newer) use a random private resolvables address, that changes at regular intervals, but can be calculated from the IRK. And as you write, this makes whitelisting not usable unless they are paired or bonded. This post has some more info on the subject.