摘要 |
<p>A communication system comprising a plurality of nodes, the communication system being arranged to assign each of the plurality of nodes a certificate by means of which it can authenticate itself to other nodes in the communication system, the communication system further comprising an authentication node arranged to determine that a certificate should be revoked and to, responsive to that determination, write an indicator of that certificate's revocation to a location in the communication system that is external to the authentication node and to which the node assigned the revoked certificate is not permitted to write.</p> |