Entrust Technologies Limited

Ian H Curry

Paul C Van Oorschot

Michael James Wiener

Stephen William Hillier

Glenn C Langford

James Arthur Turnbull

A method for securing group communications with reduced message overhead begins by initiating a secure group communication, where a group communication is secured based on security credentials of the group. The secured group communication is then provided to members of the group, where the secured group communication includes a secured message portion and an overhead portion based on the group, not each member. Each member of the group that receives the message determines that the secured message is group communication for its particular group. Each member then obtains at least a portion of the security credentials (e.g., the private decryption key) of the group to decrypt the secured group communication.

Method and apparatus for secure group communications

A method and apparatus constructs a preferred certificate chain, such as a list of all certificate authorities in a shortest trusted path, based on generated certificate chain data, such as a table of trust relationships among certificate issuing units in a community of interest, to facilitate rapid validity determination of the certificate by a requesting unit. In one embodiment, requesting units, such as certificate validation units or subscribers, send queries to a common certificate chain constructing unit. Each query may identify a beginning and target certification authority in the community. The certificate chain constructing unit then automatically determines the certification chain among certification issuing units between the beginning and target certification authorities for each query and provides certificate chain data to the requesting unit. The requesting unit then performs validity determination on the certificate to be validated based on the certificate chain data.

Method and apparatus for use in determining validity of a certificate in

A computer network security system provides generation of a certificate revocation list (CRL) upon each revocation. The entire certificate revocation list may be published on demand, or only the portion that has changed. The computer network security system provides on-demand publishing of data identifying revoked certificates, such as revocation and expiration data, in response to receipt of revocation request data. The computer network security system stores the on-demand published data for analysis by one or more network nodes, such as a client, to determine whether a certificate is valid. The network nodes include certificate revocation list cache memory that may be selectively activated/deactivated, to effect storage/non-storage of the data identifying the revoked certificates.

Computer security system and method with on demand publishing of

A method and apparatus for extending secure communication operations via shared lists is accomplished by creating a shared list in accordance with authorization parameters by one user and subsequently accessing the shared list via the authorization parameters by this and other users. To create the list, a user within the secured communication system determines whether it has been enabled, or authorized, to create a shared list. If so, the user identifies at least one other user to be added to the shared list. Having identified another user, the user creating the shared list verifies that the secure communication parameters (which includes a public key certificate of an end-user or of a certification authority) it has received regarding the another user is trustworthy. If the secure communication parameters are identified as trustworthy, the secure communication parameters of the another user are added to the shared list. To authenticate the shared list, the user creating the list digitally signs it. Once the shared list is created, other users, if authorized, may access the shared list to obtain certificates (e.g., encryption and/or signature verification certificates) of the users contained in the list.

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Kanata, Canada

Ian H Curry