1.1.2 Key Derivation Function

The ATECC608B supports the key derivation function (KDF), which derives the KDF key from the premaster secret key. The final derived KDF key is mainly used in TLS transactions. The ATECC608B supports three key derivation functions: Pseudo Random Function (PRF), AES and HMAC-Based Extract-and-Expand KDF (HKDF). The PRF is used in TLS version 1.2 and the HKDF is used in TLS version 1.3.