Please help check IO Capability Handling

[CanWang001]

Hi Bumble Team,

I’ve been using the on_authentication_user_confirmation_request method in device.py and noticed that some IO capability combinations currently result in na (not available) methods, which may be incomplete.
For example,

• when peer_io_capability is KEYBOARD_ONLY and local_io_capability is DISPLAY_YES_NO, the method is currently marked as na, but based on the IO capability logic, it should be: display_number for the local device and passkey_entry for the remote device

Do you have any plans to implement these missing cases?

Additionally, I found a few combinations that seem to be incorrectly mapped:
For example,

• when both peer_io_capability and local_io_capability are DISPLAY_ONLY, the method should be auto_confirm, not display_auto_confirm.
• when peer_io_capability is NO_INPUT_NO_OUTPUT and local_io_capability is DISPLAY_ONLY, the method should also be auto_confirm, not confirm.

Could you please help verify these mappings and let me know if any updates are planned?

Thanks for your time and support!

Best Regards,
Can Wang

[barbibulle]

It looks like you're right about some combinations being marked as na incorrectly. In fact, there really shouldn't be a need for na at all, since all combinations should be possible. I will double check that and submit a fix.
Regarding the case where both devices are DISPLAY_ONLY, however, my reading of the spec is that both devices should display the code and auto-confirm. I know, it doesn't make much sense, since there will be no time for the user to see it, but if we look at the spec, Vol 2, Part F, section 4.2.10 Numeric Comparison, it says "If both devices have output
capabilities, this step requires the displaying of a user confirmation value".

[CanWang001]

Hi Barbibulle,

Thanks for your reply.

Regarding the case where both devices are DISPLAY_ONLY, it results in the Just Works pairing method. For the Just Works, in the spec, Vol 2, Part F, section 4.2.10 Numeric Comparison, there is another statement: "The sequence for Just Works is identical to that of Numeric Comparison with the exception that the Host will not show the numbers to the user". For this statement: "If both devices have output capabilities, this step requires the displaying of a user confirmation value.", it should apply to DISPLAY_YES_NO for both devices with MITM set.

Additionally, I’d like to correct a previous statement. For this case, both the local and remote devices should use auto_confirm,

when peer_io_capability is KEYBOARD_ONLY and local_io_capability is DISPLAY_YES_NO, the method is currently marked as na, but based on the IO capability logic, it should be: display_number for the local device and passkey_entry for the remote device

because when on_authentication_user_confirmation_request is called on this case the MITM must be not required. If MITM is required, on_authentication_user_passkey_notification will be called instead and in the on_authentication_user_passkey_notification the display_number will be called.