What is the meaning of OOB(Out Of Band)??

[JoonDong]

I don't understand OOB used in BLE security part.

Is this a communication out of 2.4 ~ 2.48 GHz frequency band?

Or is this one of method of pairing procedure(to generate TK)?

Please let me know about OOB Authentication Data and OOB Procedure.

[dingari]

From what I understand, yes. OOB pairing is a way of sharing the encryption keys by some other means than the 2.4GHz band.

With MITM, there is still 1 in a million chance that a hacker may get access to all the informaiton. To address such concerns, BLE protocl provides a feature called Out-of-Band (OOB) Pairing. In this mode of pairing, instead of sharing the secret keys over the 2.4 GHz band used by the BLE protocol, it makes use of other mediums such as the Near Field Communication (NFC). Once, the secret keys are exchanged it then encrypts the channel to ensure the highest level of security.

Taken from www.cypress.com/.../project-032-oob-pairing

[Sigurd]

Hi,

We have a blog post about the different pairing methods here, including OOB. With the release of Android Nougat(version 7) last year, support for pairing with NFC using the OOB method was included. You can read more about this here.

[Øyvind]

"Out of band" in this context mean any method not involving transferring the data over the Bluetooth link. It can be, as mentioned above, over NFC, but it can also be any other protocol or anything else you can imagine, including hardcoded data from factory.

[awneil]

The 2.4GHz is not relevant here.

"Out-of-Band" means "not in the main communication channel" - so, in the case of Bluetooth, that means "not using Bluetooth".

Therefore, you could use a different 2.4GHz protocol - such as WiFi or Zigbee or 6LoWPAN or IEEE 802.15.4. or ...

[JoonDong]

Thank you. I understand OOB.