'Ask the L{KnownHostsFile} provider available on the factory which
created this protocol this protocol to verify the given host key.
@return: A L{Deferred} which fires with the result of
L{KnownHostsFile.verifyHostKey}.'

def verifyHostKey(self, hostKey, fingerprint):

    hostname = self.creator.hostname
    ip = networkString(self.transport.getPeer().host)
    self._state = 'SECURING'
    d = self.creator.knownHosts.verifyHostKey(self.creator.ui, hostname, ip, Key.fromString(hostKey))
    d.addErrback(self._saveHostKeyFailure)
    return d
