tls_prf_sha256() function

tls_prf_sha256 - Pseudo-Random Function for TLS v1.2 (P_SHA256, RFC 5246) @secret: Key for PRF @secret_len: Length of the key in bytes @label: A unique label for each purpose of the PRF @seed: Seed value to bind into the key @seed_len: Length of the seed @out: Buffer for the generated pseudo-random key @outlen: Number of bytes of key to generate Returns: 0 on success, -1 on failure. This function is used to derive new, cryptographically separate keys from a given key in TLS. This PRF is defined in RFC 2246, Chapter 5.