wolfSSL is a commercial grade TLS library available in open-source GPL form on GitHub (http://github.com/wolfSSL/wolfssl) written in C and designed for Embedded use because its modular design. They provide build-time options for enabling and disabling all algorithms and TLS features. They support progressive algorithms such as Ed25519/Curve25519, ChaCha20/Poly1035 and SHA-3 using TLS 1.2/TLS 1.3. The part used for the demo is an STM32F777ZI. They are going to add support for ARMv8-M TrustZone-M hardware security when chipsets become available in the near future.