Is L2CAP channel communication encrypted for bonded devices?

[Juju]

Hello

I have a nRF52 based device communicating with Smartphones via an encrypted characteristic (SEC_JUST_WORKS) so pairing is triggered and established.

The encrypted characteristic is used for logic exchange. But sometimes I need to send extra data so I use a L2CAP channel (PSM 0x0025) for better performance.

Since pairing was performed between the 2 devices, does this mean that encryption will be enabled transparently to transmit data over the L2CAP channel or encryption is only enabled when communicating over encrypted characteristics?

Many thanks for your help!

[Hung Bui]

Hi Juju, 

The BLE encryption actually happens on Link layer which is inside the controller, under the host. When L2CAP is in the host on top of the controller. So the data encryption is transparent to the L2CAP channel and the data sending over the air is encrypted.