Patent ID: 8856516

Claim:
A communication system comprising a plurality of nodes and an authentication node, the plurality of nodes communicatively coupled to each other and to the authentication node, the communication system configured to perform operations comprising: assigning, by the authentication node, a certificate to a node of the plurality of nodes, usable by the node to authenticate the node to other nodes in the communication system; compressing, by the authentication node, a data set representing validity of certificates assigned to the plurality of nodes to form an update to distribute to the plurality of nodes, the update being such that the update may not unambiguously provide a determination that a particular certificate is valid; periodically distributing the update to the plurality of nodes, effective to enable the nodes to store the update; generating, at the authentication node, a source of information about the validity of the plurality of certificates that is different from the update, effective to enable resolution of an ambiguity in the update regarding the validity of the particular certificate; transmitting the source of information from the authentication node to one or more nodes of the plurality of nodes, effective to enable the source of information to be stored in the one or more nodes; determining that a specific certificate should be revoked; and responsive to the determining, the authentication node writing an indicator of the revocation of the specific certificate to one or more of the plurality of nodes as the source of information about the validity of the specific certificate.