Abstract: 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.

Abstract: 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.