Amazon FreeRTOS
User Guide

Transport Layer Security

The Transport Layer Security (TLS) interface is a thin, optional wrapper used to abstract cryptographic implementation details away from the Secure Sockets interface above it in the protocol stack. The purpose of the TLS interface is to make the current software crypto library, mbed TLS, easy to replace with an alternative implementation for TLS protocol negotiation and cryptographic primitives. The TLS library can be swapped out without any changes required to the Secure Sockets interface. See aws_tls.h in the Amazon FreeRTOS source code repository.

The TLS library is optional because you can choose to interface directly from Secure Sockets into a crypto library. The Amazon FreeRTOS library is not used for MCU solutions that include a full-stack offload implementation of TLS and network transport.