Delete one side bond info,Cannot pair again

[Martin Evans]

Dear Nordic Team,

I am programming with ncs V2.9.0 and nrf52833.

There is a trouble happend when one side delete the pairing info,but the other not.

Peripheral has already forgot the info,But central still maintain it.And then central side will report this LOG.

I want to pair with it again WHENEVER WHATEVER happened.HOW I can do to avoid it?

Best regard.

Martin

[Simonr]

Hi Martin

This is the expected behavior when doing bonding with BLE. If one device still remembers the bonding it won't be able to bond with the device that has deleted the bonding information again as it still thinks it is bonded. This is part of the Bluetooth LE specification.

If you add a way to erase the bonds on the other side either upon a disconnect or upon a failed connection/bonding attempt. Alternatively, don't erase the bonding info from one side in the first place.

Best regards,

Simon

[Martin Evans]

Hi Simonr,

I have never delete bonded info at any side,but our product happend.

So I have to find out one way to solve or aviod this phenomenon.Do there any suggestions?

Thanks

Best regard

Martin

[Simonr]

Martin Evans said:

I have never delete bonded info at any side,but our product happend.

I'm not sure I understand this statement, can you explain. Which side is deleting the bonding info in the first place? 

If you add a way to erase the bonds on the other side either upon a disconnect or upon a failed connection/bonding attempt that should be a way around this. The other alternative is to not have bonding if you don't need the security features it provides in your product.

Best regards,

Simon

[Turbo J]

If you already shipped the products it will have to be a recall.

The BTLE examples leave out some functionality in order to make the code easier to understand and learn how it works.

For real world products you need to add code that for example handles pairing mode and can delete bonds in specific situations like the one described above. This has to be an explicit user interaction here.

HID devices require correct handling of bonding information as these devices always have security implications...

[Martin Evans]

Hi Simonr,

Sorry for unclear explanation.

What I mean is that I never done any operation to delete any sides' bonding info,But now one side(exactly  peripheral one) lost this info for the unknow reason.

Same problem happened in our forectory but solved by deleting both sides' info.But cannot solve those happed in our customs'.

And another question,How to delte security?I would to get it a try.

Best regards,

Martin

[Martin Evans]

Hi Turbo J,

I wonder could HID devices bonding without security?

Best regard,

Martin

[Simonr]

Devices can not bond without any type of security I'm afraid. Removing all the BLE security would also remove all bonding/pairing features I'm afraid. 

Best regards,

Simon

[Martin Evans]

Hi Simonr,

The newest information that by deleting both sides info,this problem is solved.But now we still dont know how this happened.Haha╮(╯▽╰)╭

Best regard

Martin