ble_app_gls donot use LESC

Hi Kai,

MITM protection (SEC_PARAM_MITM) is not possible when SEC_PARAM_IO_CAPABILITIES is set to BLE_GAP_IO_CAPS_NONE. This probably explains the error. Have you tried to disable MITM?

Best regards,

Vidar

Hi Vidar,

I  just disabled MITM and the device can connect.

But when I access characteristic the device automatically disconnects.

Hi Kai,

You have to make a few more changes as the example is set up to require MITM protection by default. It should work if you comment these sections:

Hi Vidar,

First, let me reply this message.

user4240 said:

You have to make a few more changes as the example is set up to require MITM protection by default. It should work if you comment these sections:

It can work now.

Second,I want to tell you about the project I am testing.

I am testing this pairing table :

And set the security level to the characteristic :

Based on the combination of pairing table and security level, I have listed one of the test items:

What is the result of my purpose for these combinations to actually run.

I am confused about the choice of security level and the setting of pairing parameters.

Hi Kai,

The SEC_PARAM_* symbols define the security capabilities of your device. E.g. if LESC and MITM pairing is supported. But it will not prevent a central from initiating pairing with lower security. For instance, legacy just works.

The security requirements is controlled by the security level configured for your characteristics in service_init():

So you will still be able to pair without MITM even if the SEC_PARAM_MITM bit is set, but then you will only be able to access characteristics that has the security level set to "SEC_OPEN" or "SEC_JUST_WORKS".

Hi Vidar,

I'm doing these combinations for explore the problem of data encryption.

I don't know if the data encryption is because SEC_PARAM_MITM is set or SEC_MITM is set.

Among them, the security level selection just works will also have encryption.

The following shows the results I actually tested through the example code and Sniffer.

Hi Vidar,

I'm doing these combinations for explore the problem of data encryption.

I don't know if the data encryption is because SEC_PARAM_MITM is set or SEC_MITM is set.

Among them, the security level selection just works will also have encryption.

The following shows the results I actually tested through the example code and Sniffer.

Hi Kai,

The link will become encrypted regardless of what pairing method you use. The difference when using LESC is that the sniffer will not be able to pick up the encryption key during the key exchange, so it will not be able to decrypt the communication between your devices.

Sniffing a connection between bonded devices

Hi Vidar,

user4240 said:

The link will become encrypted regardless of what pairing method you use.

Can this passage reveal a little more information?

Hi Kai,

I think you will find the resources below useful. The purpose of the pairing procedure is to securely exchange keys that later are used to encrypt the link, and it's the security of this exchange that differs between the different pairing methods.

https://www.bluetooth.com/blog/bluetooth-pairing-part-1-pairing-feature-exchange/

https://www.bluetooth.com/blog/bluetooth-pairing-part-2-key-generation-methods/

https://www.bluetooth.com/blog/bluetooth-pairing-passkey-entry/

https://www.bluetooth.com/blog/bluetooth-pairing-part-4/

https://www.bluetooth.com/bluetooth-resources/intro-to-bluetooth-security-part1/

https://www.bluetooth.com/bluetooth-resources/intro-to-bluetooth-security-part2/

Hi Vidar,

OK I'll take a look.

Thank you!!