BLE Out of band (OOB) pairing on iOS (13+)

Question

I'm working on an iOS application (for iOS 13+), that should use the most secure BLE pairing method, Out of Band pairing (OOB) (which usually uses an NFC tag for BLE address/temporary key (TK) storage).

Unfortunately, either my Google skills suck, or there is literally no useful information on Google for OOB pairing in iOS..

From my understanding, Apple is already using some OOB technique to pair with the Apple watch (through an image rather than NFC, with fallback to passkey).

During my Google research I've found one single link to StackOverflow, Bluetooth “out of band” (OOB) pairing on iOS?, which raises the same question, but it's from September 2015, so the answer there is (hopefully) outdated!

Also, having had a look at CoreBluetooth API, it seems like there is no information in there on OOB pairing..

> Does anyone have more (up-to-date) information on this topic?

Any link/clue/explanation is much appreciated!

(I can't believe really, that this hasn't been implemented in iOS as of today..)

Gabrielegabriell

Apps have no direct control over the bonding process in Core Bluetooth. Accessing an encrypted characteristic will trigger the bonding process, which is handled by iOS. I believe that passcode is the only unsupported method – Waterway

@Waterway Thanks for your comment. I've indeed read about reading protected/encrypted characteristic to trigger bonding, but this doesn't really help me with the OOB pairing.. I guess you meant "is the only supported method"? (In that case, there seems to be no other option than using passkey for pairing in 2019..) – Gabrielegabriell

Sorry, yes. That was a typo. It should have been supported – Waterway

Hello, did you manage to get OOB over NFC on iOS? On Android, since 7.1, we just touch the phone to the NFC antenna and bonding starts automatically (just with a popup with Yes/No). On iOS we can't get it to work in any way. Tested on iPhone 13 Pro and iOS 15.3.1. – Crummy

Has there been any further development in this question? And has anyone tried initiating the paring initiated from a NFC handover (mime “application/vnd.bluetooth.le.oob”) or something like that? – Octachord