What Are Authentication and Pairing Function of BLE Module?

From the protocol perspective:

Authentication: The authentication is used for checking device identity by UART data, which is only effective for APP. How to use the authentication function? Enable the authentication function and set a password for authentication for the slave device. When the master connects to the slave, the master must send the pre-set password in the authentication channel. After the slave receives the password, it will check whether the password is the same as the pre-set one. If yes, the connection will be kept if no, the connection will be disabled.

Pairing: The pairing is supported by the Bluetooth underlying protocol. It will save the paired device in the pairing list. No matter what device for the master part is: a module or a mobile phone, it supports the paring function.

From the function perspective:

Authentication: The authentication requires the password in the channel for each connection.

Pairing: The pairing supports the direct connection without a password after the first pairing is set. Only the MAC address of the pre-pairing device is deleted in the pairing list, there will be a password needed to set the connection again.