http://www.rfc-editor.org/rfc/rfc4398.txt
RFC 4398: Storing Certificates in the Domain Name System (DNS), S. Josefsson2006-03-01T23:00:00-00:00Cryptographic public keys are frequently published, and their authenticity is demonstrated by certificates. A CERT resource record (RR) is defined so that such certificates and related certificate revocation lists can be stored in the Domain Name System (DNS). [STANDARDS-TRACK]