This object is the name of a globally configured key
chain. It is used to enable authentication and determine
the set of keys which may be used on a particular group.
If ccaHCCPGroupAuthentication is text(3), it is used as the
authentication password.
If ccaHCCPGroupAuthentication is md5(2), it is used as the
message digest for md5.
If a key chain has not been configured, no authentication
is performed on that group.