BLE communication interaction between bonded appliances.

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KaKo_4288106
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Hi All,

I’ve been trying to better understand the Cypress operation based on a certain scenarios but have not had any luck getting a solid answer from the BLE datasheets and cypress BLE functions

What I am trying to do is get a better understanding of how communication between bonded appliances changes based on one or the other losing its bonding info
Scenario 1) Two bonded Cypress appliances, the central has its bonding list cleared

Scenario 2) Two bonded Cypress appliances, the peripheral has its bonding list cleared

I understand that the BLE stack handles this operation for us but I want to better understand how it handles edge cases.

That why I want to know how the two appliances determine that both have the necessary bonding information and what happens when this communication results in the Master or the Slave discovering that the other does not have the same information.

I can see that the GAP functions associated with the process but checking the contents of the functions does not give much info on what is actually happening behind the scenes.
    CYBLE_EVT_GAP_AUTH_COMPLETE,

     The event parameter contains the security information as defined by CYBLE_GAP_AUTH_INFO_T.

     This event is generated at the end of the following three operations:

    * Authentication is initiated with a newly connected device

    * Encryption is initiated with a connected device that is already bonded

    * Re-Encryption is initiated with a connected device with link already encrypted

     During encryption/re-encryption, the Encryption Information exchanged during the pairing process

     is used to encrypt/re-encrypt the link. As this does not modify any of the authentication

     parameters with which the devices were paired, this event is generated with NULL event data

     and the result of the encryption operation. */

Thanks in advance.

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Yugandhar
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500 solutions authored 1000 replies posted 5 likes given

Hello KaKo_4288106 ,

Bluetooth pairing is the process where the Devices exchange their identity information in order to set up a trusted relationship and generate encryption keys used for data exchange. Bonding refers to the storage of the security keys so they can be used later. Once bonded, if any device(Central or Peripheral) clears the bonded data information, then after reconnection these devices will go for the pairing process again.

Please refer to the BLE_Bonding example project from the GitHub for more information on storing and removing of bonding data. Please refer to the attached CySmart log files for reference. These files have the information of two devices which are 1. Connecting without stored bonded information and 2. Connecting with stored bonding information.

Thanks,

P Yugandhar.

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Yugandhar
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500 solutions authored 1000 replies posted 5 likes given

Hello KaKo_4288106 ,

Bluetooth pairing is the process where the Devices exchange their identity information in order to set up a trusted relationship and generate encryption keys used for data exchange. Bonding refers to the storage of the security keys so they can be used later. Once bonded, if any device(Central or Peripheral) clears the bonded data information, then after reconnection these devices will go for the pairing process again.

Please refer to the BLE_Bonding example project from the GitHub for more information on storing and removing of bonding data. Please refer to the attached CySmart log files for reference. These files have the information of two devices which are 1. Connecting without stored bonded information and 2. Connecting with stored bonding information.

Thanks,

P Yugandhar.

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