A Secure/Multipurpose Internet Mail Extensions (S/MIME) key material publication system that converts cryptographic material extracted from digitally signed and validated S/MIME messages it receives into key material formats suitable for populating email address books. Publication of the address book contents both internal and external to an organization is done using the standard address book lightweight database access protocol (LDAP). The wide availability and coordination of such automated address books distributing key material across the Internet allows the large installed base of S/MIME email clients to immediately send secure encrypted email across organizational boundaries. The system serves the role of public key server thus removing a barrier to ubiquitous secure encrypted email by simplifying global key management.