The MD5 authentication key. When setting this object, the
usdOspfIfMd5AuthKeyId must be specified on the same PDU. For simple
text authentication type, use ospfIfAuthKey. Setting this object will
have the side effect of adding or updating the correspondent entry in
usdOspfMd5IntfKeyTable. If key given has less than 16 octets, such value
will be appended with zeros to complete 16 octets. The zeros will
appended to the right of the given key. Reading this object always
results in an OCTET STRING of length zero.