The KDF define in RFC 5295 is very similar to HKDF-Expand() defined in
RFC 5869. Allow a NULL label to be used to select the RFC 5869 version
with arbitrary seed (info in RFC 5869) material without forcing the
label and NULL termination to be included. HKDF-Expand() will be needed
for OWE.
Signed-off-by: Jouni Malinen <j@w1.fi>
The local T[] buffer may contain parts of the derived key, so clear it
explicitly to minimize number of unnecessary copies of key material in
memory.
Signed-off-by: Jouni Malinen <j@w1.fi>
