'Called back if the user did not sent a signature.  If reason is
error.ValidPublicKey then this key is valid for the user to
authenticate with.  Send MSG_USERAUTH_PK_OK.'

def _ebCheckKey(self, reason, packet):

    reason.trap(error.ValidPublicKey)
    self.transport.sendPacket(MSG_USERAUTH_PK_OK, packet)
    return failure.Failure(error.IgnoreAuthentication())
