1.4.2 Security Abstraction Layer (SAL)

The Security Abstraction Layer (SAL) provides an API that allows access to low level AES engine functions abstraction to encrypt and decrypt frames.

These functions are actually implemented dependent on the underlying hardware, for example, the AES engine of the transceiver/microcontroller. The API provides functions to set up the proper security key, security scheme (ECB or CBC), and direction (encryption or decryption).

SAL is responsible for using the hardware accelerators for encryption and authentication.

The CCM encryption mode is utilized for performing encryption and authentication processes.

Wolf crypto library can be utilized to provide varying levels of security, including options for encryption and authentication (MIC), as well as different lengths of MIC.