The Authentication Key. This object is set according to
the value of the 'vrrpOperAuthType' object
('simpleTextPassword' or 'ipAuthenticationHeader'). If the
length of the value is less than 16 octets, the agent will
left adjust and zero fill to 16 octets. The value of this
object is the same for a given ifIndex.
When read, vrrpOperAuthKey always returns an Octet String
of length zero.