| 1939 | Post Office Protocol - Version 3J. Myers, M. Rose | Internet Standard | May 1996 |
| 2045 | Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message BodiesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 2119 | Key words for use in RFCs to Indicate Requirement LevelsS. Bradner | Best Current Practice | March 1997 |
| 3156 | MIME Security with OpenPGPM. Elkins, D. Del Torto, R. Levien, T. Roessler | Proposed Standard | August 2001 |
| 3207 | SMTP Service Extension for Secure SMTP over Transport Layer SecurityP. Hoffman | Proposed Standard | February 2002 |
| 3274 | Compressed Data Content Type for Cryptographic Message Syntax (CMS)P. Gutmann | Proposed Standard | June 2002 |
| 3370 | Cryptographic Message Syntax (CMS) AlgorithmsR. Housley | Proposed Standard | September 2002 |
| 4289 | Multipurpose Internet Mail Extensions (MIME) Part Four: Registration ProceduresN. Freed, J. Klensin | Best Current Practice | December 2005 |
| 4511 | Lightweight Directory Access Protocol (LDAP): The ProtocolJ. Sermersheim, Ed. | Proposed Standard | June 2006 |
| 5322 | Internet Message FormatP. Resnick, Ed. | Draft Standard | October 2008 |
| 5890 | Internationalized Domain Names for Applications (IDNA): Definitions and Document FrameworkJ. Klensin | Proposed Standard | August 2010 |
| 6376 | DomainKeys Identified Mail (DKIM) SignaturesD. Crocker, Ed., T. Hansen, Ed., M. Kucherawy, Ed. | Internet Standard | September 2011 |
| 6409 | Message Submission for MailR. Gellens, J. Klensin | Internet Standard | November 2011 |
| 6532 | Internationalized Email HeadersA. Yang, S. Steele, N. Freed | Proposed Standard | February 2012 |
| 7292 | PKCS #12: Personal Information Exchange Syntax v1.1K. Moriarty, Ed., M. Nystrom, S. Parkinson, A. Rusch, M. Scott | Informational | July 2014 |
| 7435 | Opportunistic Security: Some Protection Most of the TimeV. Dukhovni | Informational | December 2014 |
| 7841 | RFC Streams, Headers, and BoilerplatesJ. Halpern, Ed., L. Daigle, Ed., O. Kolkman, Ed. | Informational | May 2016 |
| 7929 | DNS-Based Authentication of Named Entities (DANE) Bindings for OpenPGPP. Wouters | Experimental | August 2016 |
| 8162 | Using Secure DNS to Associate Certificates with Domain Names for S/MIMEP. Hoffman, J. Schlyter | Experimental | May 2017 |
| 8174 | Ambiguity of Uppercase vs Lowercase in RFC 2119 Key WordsB. Leiba | Best Current Practice | May 2017 |
| 8551 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 4.0 Message SpecificationJ. Schaad, B. Ramsdell, S. Turner | Proposed Standard | April 2019 |
| 8621 | The JSON Meta Application Protocol (JMAP) for MailN. Jenkins, C. Newman | Proposed Standard | August 2019 |
| 8823 | Extensions to Automatic Certificate Management Environment for End-User S/MIME CertificatesA. Melnikov | Informational | April 2021 |
| 9051 | Internet Message Access Protocol (IMAP) - Version 4rev2A. Melnikov, Ed., B. Leiba, Ed. | Proposed Standard | August 2021 |
| 9216 | S/MIME Example Keys and CertificatesD. K. Gillmor, Ed. | Informational | April 2022 |
| 9219 | S/MIME Signature Verification Extension to the JSON Meta Application Protocol (JMAP)A. Melnikov | Proposed Standard | April 2022 |
| 9580 | OpenPGPP. Wouters, Ed., D. Huigens, J. Winter, Y. Niibe | Proposed Standard | July 2024 |
| 9598 | Internationalized Email Addresses in X.509 CertificatesA. Melnikov, W. Chuang, C. Bonnell | Proposed Standard | May 2024 |
| 9788 | Header Protection for Cryptographically Protected EmailD. K. Gillmor, B. Hoeneisen, A. Melnikov | Proposed Standard | August 2025 |