what are the methods to secure peripheral device over ble?

[nithin]

I'm using nrf52832 in my peripheral device, I want to secure its connection via any authentication is there any method for that?, also I need to encrypt its data(characteristics).

[endnode]

In BLE there is Security Manager layer as the only one standard procedure. It has several modes depending on standard and Input/Output methods support on both devices while only some of these are completely safe against well known attacks. However for your use case it should be enough, please read about BLE pairing and bonding mechanisms on any BLE introduction/tutorial which will pop up in Google search (e.g. microchipdeveloper.com/wireless:ble-gap-security )

The other method (e.g. in case BLE Security Manager layer pairing/bonding concept doesn't fit your use cases) is custom security scheme on APP layer. Here is one example how this could work (but surely there are many many more ways): devzone.nordicsemi.com/.../