Read operation failed: ATTERR_INSUF_ENC_KEY_SIZE(0x010C)

[migi]

I use the following :

->nRF52840 Dongle / µC on the other side

->Blutooth Low Energy v3.0.1 (desctop version)

I try to read a characterictic after connecting and get the following error:

ATTERR_INSUF_ENCRYPTION(0x010F) -> this error is clear for me, because I did no pairing and my µC application requires LE secure pairing (no keyboard, no display)

but if I pair with:

• I/O capabilities: no keyboard, no display
• Authentication: Enable LE Secure connection Pairing
  • (no) Enable MITM protection
  • (no)Enable OOB data
  • (no) Enable keypress notifications
  • (no) Perform bonding

the pairing works fine, but I get the following Error:

ATTERR_INSUF_ENC_KEY_SIZE(0x010C)

so my question: is there a possibility to define the key size for the Bluetoot low energy v3.0.1 application?

• which key size is used (default key size)

If I configure my µC so that no pairing is needed for reading this specific characteristic, then everthing works fine. But I would neet secure BLE connection and offer read access only if the device is paired

thanks for your help, best wishes, migi

[Edvin]

Hello,

I think the issue is not the key size in itself, but the required security parameters you set for your service/characteristic, and the security parameters that you use in your application for pairing/bonding.

What SDK version are you using? (NCS/nRF5 SDK and version?)

How do you set the security requirement for your characteristic? Can you please share a snippet of what you change for:

If I configure my µC so that no pairing is needed for reading this specific characteristic, then everthing works fine.

What does that change look like? What did it look like before, and what does it look like after?

I think that information will shed some light on what you are doing, and how to properly set the pairing parameters to be able to access the characteristic only with the appropriate amount of security.

Best regards,

Edvin