How to decode the packets on Android or IOS when packets are encoded using ble_advdata_encode()?

[Justin]

I am using nrf52832 chip along with softdevice as a peripheral. There is a requirement wherein we want to encode the advertisement data.

Came across ble_advdata_encode() SDK function. If I encode the advt. data on peripheral, how can I decode it on central/iOS/Android device?

I am not using Pairing and bonding so will the decoding still work?

Also Will this encode the mac id of the device?

The requirement is not to advertise with the same mac ID everytime and change dynamically.

[Hung Bui]

Hi Justin, 

The ble_advdata_encode basically put the data in the correct format that defined for the ADV packet. I have a blog here discussed about advertising and the format: https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/bluetooth-smart-and-the-nordics-softdevices-part-1

You can find the breaking down of an advertising packet there. 

On the phone side you will receive the byte array that advertise. You would need to decode it the same way as it's encoded. You may want to have a look at our nrf_ble_scan.c library to see how the adv packet processed. 

Regarding MAC ID, there isn't a MAC ID term in BLE but an address of the advertiser. The address can be changed dynamically. But if you want the peer device to recognize the advertiser, you need to provide the peer device the IRK that you use to generate the device. Please read more about Random Resolvable Address. 

[Justin]

Hung Bui said:

But if you want the peer device to recognize the advertiser, you need to provide the peer device the IRK that you use to generate the device.

Hi Hung, Thanks for the explanation.

I was wondering if there is any example of IRK key generation? Also we are not using bonding and pairing process. How can I achieve the dynamic address feature?

[Hung Bui]

By default Bluetooth spec requires bonding to exchange IRK. If you are not doing any bonding and pairing, you would need to either hard code the IRK or find a way to transfer the IRK out of band (not using BLE). 

We don't have an example showing how to implement IRK but this case would probably help: https://devzone.nordicsemi.com/f/nordic-q-a/37816/ble-advertisement-----privacy-and-tracking

On the peer device you would need to put the IRK into the whitelist address when scanning. 

This task is a little bit advance so I would suggest you to get familiar with our SDK and examples, especially the advertising module, the peer manager module and the scanner module. 

There is another option is to use the EID Eddystone standard by Google. In this protocol, the credential (similar to IRK concept) is exchanged in a secure way even though there is no connection/pairing. 
Read more about that here: https://developers.google.com/beacons/eddystone-eid and here : https://infocenter.nordicsemi.com/topic/sdk_nrf5_v16.0.0/ble_sdk_app_es.html?cp=7_1_4_2_2_9