Event packet encoding

Frame format encoding of the BLE_GAP_EVT_AUTH_STATUS packet.

Event ID = 0x17 for BLE_GAP_EVT_AUTH_STATUS

All BLE Events, ble_evt_t, are encoded with the header ble_evt_hdr_t first, containing only the 'Event ID', followed by the event. The 'Event Length' will not be encoded as the size of the event could be of different sizes depending on decoder architecture.

The BLE GAP event contains a connection handle, and for the BLE GAP Authentication Status event, the ble_evt_gap_auth_status_t is encoded after connection handle as seen in Figure 1.

The security mode levels 1 and 2 are both bitfields inside 1 byte as seen in Figure 1. The same goes for The long term authentication and length.

The order of the encoding is:

- 2 bytes:		Connection Handle
- 1 byte		Authentication Status
- 1 byte:		Error Source
- 1 byte:		Security Mode levels
	- 3 bits:	sm2
	- 3 bits:	sm1
- 1 bytes		Peripheral Key Exchange
- 1 bytes		Central Key Exchange
- 2 bytes		Encryption Diversifier
- 16 bytes		Long Term Key
- 1 byte		Long Term Key Length and Auth
	- 1 bit:	Authentication
	- 5 bits:	Length
- 16 bytes		Identify Resolution Key
- 1 bytes		Address Type
- 6 bytes		Address (LSB)

Encoding of GAP Connection Security Updated event

Figure 1: Encoding of GAP Authentication Status event.