sha384_prf_bits() function

sha384_prf_bits - IEEE Std 802.11ac-2013, 11.6.1.7.2 Key derivation function @key: Key for KDF @key_len: Length of the key in bytes @label: A unique label for each purpose of the PRF @data: Extra data to bind into the key @data_len: Length of the data @buf: Buffer for the generated pseudo-random key @buf_len: Number of bits 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. If the requested buf_len is not divisible by eight, the least significant 1-7 bits of the last octet in the output are not part of the requested output.