ble oob pairing security level3

[Samuel Keller]

Hi 

I am trying to establish a ble oob pairing in legacy mode to meet security level 3.

Therefore i am using the example project peripheral_nfc_pairing and the nRF Connnect for Destoph Bluetooth Low Energy Standalone v4.0.4 App. 

In the nRF BLE App i first connect to Device. Then i initiate a pairing with  MITM Protection and OOB data. LE Secure Connnection is deactivated. 

I would expect a window to enter the temporary key, but it directly pairs in just works mode which is security level 2.

[Samuel Keller]

I am using nRF Connect SDK v2.5.0

[Samuel Keller]

Debug output:

Starting Bluetooth NFC Pairing Reference example
I: 8 Sectors of 4096 bytes
I: alloc wra: 0, eb0
I: data wra: 0, 194
I: SoftDevice Controller build revision:
I: c5 93 ba a9 14 4d 8d 05 |.....M..
I: 30 4e 9b 92 d7 71 1e e8 |0N...q..
I: aa 02 50 3c |..P<
I: HW Platform: Nordic Semiconductor (0x0002)
I: HW Variant: nRF52x (0x0002)
I: Firmware: Standard Bluetooth controller (0x00) Version 197.47763 Build 2370639017
I: No ID address. App must call settings_load()
Bluetooth initialized
I: Identity: C3:84:F4:B8:67:10 (random)
I: HCI: version 5.4 (0x0d) revision 0x1102, manufacturer 0x0059
I: LMP: version 5.4 (0x0d) subver 0x1102
Generating new pairing keys
I: Connection Handover Selector role
NFC configuration done
Regular advertising started
Connected CB:49:2A:CD:9D:6C (random)
Pairing completed: CB:49:2A:CD:9D:6C (random), bonded: 0
Security changed: CB:49:2A:CD:9D:6C (random) level 2
Generating new pairing keys

[Amanda Hsieh]

Hi, 

I am trying to establish a ble oob pairing in legacy mode to meet security level 3.

I would suggest you study https://academy.nordicsemi.com/courses/bluetooth-low-energy-fundamentals/lessons/lesson-5-bluetooth-le-security-fundamentals/ 

If you follow the Testing with NFC Poller Device instruction of peripheral_nfc_pairing, it will get security level 4. 

*** Booting nRF Connect SDK v3.5.99-ncs1 ***
Starting Bluetooth NFC Pairing Reference example
I: 8 Sectors of 4096 bytes
I: alloc wra: 0, fe8
I: data wra: 0, 0
I: SoftDevice Controller build revision: 
I: 36 f0 e5 0e 87 68 48 fb |6....hH.
I: 02 fd 9f 82 cc 32 e5 7b |.....2.{
I: 91 b1 5c ed             |..\.    
I: HW Platform: Nordic Semiconductor (0x0002)
I: HW Variant: nRF52x (0x0002)
I: Firmware: Standard Bluetooth controller (0x00) Version 54.58864 Build 1214809870
I: No ID address. App must call settings_load()
Bluetooth initialized
I: Identity: EF:06:74:2A:38:07 (random)
I: HCI: version 5.4 (0x0d) revision 0x118f, manufacturer 0x0059
I: LMP: version 5.4 (0x0d) subver 0x118f
Generating new pairing keys
I: Connection Handover Selector role
NFC configuration done
Regular advertising started
Connected 5C:0F:10:28:31:94 (random)
LESC OOB data requested
Security changed: 5C:0F:10:28:31:94 (random) level 4
Pairing completed: AC:3E:B1:12:C2:B2 (public), bonded: 1
Generating new pairing keys

Regards,
Amanda H.

[Samuel Keller]

Hi Amanda

Thanks for youre replay. I already studied the ble fundamentals lessons in details. 
Level 4 connection is working perfektly fine, but i aim to establish a level 3 connection.
And this Level 3 connection is not working. 


Thanks for further support. 

[Amanda Hsieh]

Try to enable CONFIG_BT_SMP_OOB_LEGACY_PAIR_ONLY in the prj.conf.