[BLE--SMP] SMP protocol for Bluetooth security management

Briefly

SMP is the security Manager Protocol. Its content is mainly pairing and key distribution, and then using key to the link or data encryption. Reference Articles

Before you understand the SMP protocol, you need some prior knowledge of BLE security management to refer to:
Introduction to the SMP security management of Bluetooth
Pairing method of Bluetooth security management SM
Safe l2cap Channel of Bluetooth security management ble

SMP data is through the L2cap fixed channel –security Manager channel, for without Le secure connections, L2CAP Channel's MTU is 23, for the Le Secure Connections, the MTU of the L2CAP channel is 65. SMP command Format

Two pictures to understand:

SMP Timeout

When SMP is in progress, the command timeout is 30s, and if the next command is in place, the SMP timer will be reset, and only the timer will trigger the timeout when it reaches 30s, causing the SMP process to terminate.

For the various command of SMP and its contents, use direct reference to the spec.