31. A system for locating a certificate for an electronic messaging system, the system comprising: a plurality of devices capable of sending and receiving electronic messages; a server for processing at least some electronic messages; program logic executable by a processor and operable to search for a certificate of a sender or a recipient of an electronic message based on a canonical name associated with an address of the sender or the recipient respectively, wherein the address of the sender or the recipient comprises at least a first user name and at least a first domain name, and wherein the canonical name is the address of the sender or the recipient with both the first domain name truncated to identify a second domain name and the first user name truncated to identify a second user name.
31. A system for locating a certificate for an electronic messaging system, the system comprising: a plurality of devices capable of sending and receiving electronic messages; a server for processing at least some electronic messages; program logic executable by a processor and operable to search for a certificate of a sender or a recipient of an electronic message based on a canonical name associated with an address of the sender or the recipient respectively, wherein the address of the sender or the recipient comprises at least a first user name and at least a first domain name, and wherein the canonical name is the address of the sender or the recipient with both the first domain name truncated to identify a second domain name and the first user name truncated to identify a second user name. 39. The system according to claim 31 , wherein said canonical name comprises at least one of multiple canonical domain names and multiple canonical user names.