| 9788 | Header Protection for Cryptographically Protected EmailD. K. Gillmor, B. Hoeneisen, A. Melnikov | Proposed Standard | August 2025 |
| 9052 | CBOR Object Signing and Encryption (COSE): Structures and ProcessJ. Schaad | Internet Standard | August 2022 |
| 8551 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 4.0 Message SpecificationJ. Schaad, B. Ramsdell, S. Turner | Proposed Standard | April 2019 |
| 8550 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 4.0 Certificate HandlingJ. Schaad, B. Ramsdell, S. Turner | Proposed Standard | April 2019 |
| 7114 | Creation of a Registry for smime-type Parameter ValuesB. Leiba | Proposed Standard | January 2014 |
| 7107 | Object Identifier Registry for the S/MIME Mail Security Working GroupR. Housley | Informational | January 2014 |
| 6268 | Additional New ASN.1 Modules for the Cryptographic Message Syntax (CMS) and the Public Key Infrastructure Using X.509 (PKIX)J. Schaad, S. Turner | Informational | July 2011 |
| 5990 | Use of the RSA-KEM Key Transport Algorithm in the Cryptographic Message Syntax (CMS)J. Randall, B. Kaliski, J. Brainard, S. Turner · obsoleted by RFC 9690 | Proposed Standard | September 2010 |
| 5912 | New ASN.1 Modules for the Public Key Infrastructure Using X.509 (PKIX)P. Hoffman, J. Schaad | Informational | June 2010 |
| 5911 | New ASN.1 Modules for Cryptographic Message Syntax (CMS) and S/MIMEP. Hoffman, J. Schaad | Informational | June 2010 |
| 5751 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.2 Message SpecificationB. Ramsdell, S. Turner · obsoleted by RFC 8551 | Proposed Standard | January 2010 |
| 5750 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.2 Certificate HandlingB. Ramsdell, S. Turner · obsoleted by RFC 8550 | Proposed Standard | January 2010 |
| 5703 | Sieve Email Filtering: MIME Part Tests, Iteration, Extraction, Replacement, and EnclosureT. Hansen, C. Daboo | Proposed Standard | October 2009 |
| 5655 | Specification of the IP Flow Information Export (IPFIX) File FormatB. Trammell, E. Boschi, L. Mark, T. Zseby, A. Wagner | Proposed Standard | October 2009 |
| 5652 | Cryptographic Message Syntax (CMS)R. Housley | Internet Standard | September 2009 |
| 5621 | Message Body Handling in the Session Initiation Protocol (SIP)G. Camarillo | Proposed Standard | September 2009 |
| 5616 | Streaming Internet Messaging AttachmentsN. Cook | Informational | August 2009 |
| 5598 | Internet Mail ArchitectureD. Crocker | Informational | July 2009 |
| 5585 | DomainKeys Identified Mail (DKIM) Service OverviewT. Hansen, D. Crocker, P. Hallam-Baker | Informational | July 2009 |
| 5547 | A Session Description Protocol (SDP) Offer/Answer Mechanism to Enable File TransferM. Garcia-Martin, M. Isomaki, G. Camarillo, S. Loreto, P. Kyzivat | Proposed Standard | May 2009 |
| 5536 | Netnews Article FormatK. Murchison, Ed., C. Lindsey, D. Kohn | Proposed Standard | November 2009 |
| 5485 | Digital Signatures on Internet-Draft DocumentsR. Housley | Informational | March 2009 |
| 5432 | Quality of Service (QoS) Mechanism Selection in the Session Description Protocol (SDP)J. Polk, S. Dhesikan, G. Camarillo | Proposed Standard | March 2009 |
| 5405 | Unicast UDP Usage Guidelines for Application DesignersL. Eggert, G. Fairhurst · obsoleted by RFC 8085 | Best Current Practice | November 2008 |
| 5402 | Compressed Data within an Internet Electronic Data Interchange (EDI) MessageT. Harding, Ed. | Informational | February 2010 |
| 5365 | Multiple-Recipient MESSAGE Requests in the Session Initiation Protocol (SIP)M. Garcia-Martin, G. Camarillo | Proposed Standard | October 2008 |
| 5364 | Extensible Markup Language (XML) Format Extension for Representing Copy Control Attributes in Resource ListsM. Garcia-Martin, G. Camarillo | Proposed Standard | October 2008 |
| 5321 | Simple Mail Transfer ProtocolJ. Klensin | Draft Standard | October 2008 |
| 5293 | Sieve Email Filtering: Editheader ExtensionJ. Degener, P. Guenther | Proposed Standard | August 2008 |
| 5275 | CMS Symmetric Key Management and DistributionS. Turner | Proposed Standard | June 2008 |
| 5273 | Certificate Management over CMS (CMC): Transport ProtocolsJ. Schaad, M. Myers · obsoleted by RFC 10003 | Proposed Standard | June 2008 |
| 5126 | CMS Advanced Electronic Signatures (CAdES)D. Pinkas, N. Pope, J. Ross | Informational | March 2008 |
| 5124 | Extended Secure RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/SAVPF)J. Ott, E. Carrara | Proposed Standard | February 2008 |
| 5090 | RADIUS Extension for Digest AuthenticationB. Sterman, D. Sadolevsky, D. Schwartz, D. Williams, W. Beck | Proposed Standard | February 2008 |
| 5039 | The Session Initiation Protocol (SIP) and SpamJ. Rosenberg, C. Jennings | Informational | January 2008 |
| 5008 | Suite B in Secure/Multipurpose Internet Mail Extensions (S/MIME)R. Housley, J. Solinas · obsoleted by RFC 6318 | Historic | September 2007 |
| 4976 | Relay Extensions for the Message Sessions Relay Protocol (MSRP)C. Jennings, R. Mahy, A. B. Roach | Proposed Standard | September 2007 |
| 4975 | The Message Session Relay Protocol (MSRP)B. Campbell, Ed., R. Mahy, Ed., C. Jennings, Ed. | Proposed Standard | September 2007 |
| 4954 | SMTP Service Extension for AuthenticationR. Siemborski, Ed., A. Melnikov, Ed. | Proposed Standard | July 2007 |
| 4952 | Overview and Framework for Internationalized EmailJ. Klensin, Y. Ko · obsoleted by RFC 6530 | Informational | July 2007 |
| 4949 | Internet Security Glossary, Version 2R. Shirey | Informational | August 2007 |
| 4871 | DomainKeys Identified Mail (DKIM) SignaturesE. Allman, J. Callas, M. Delany, M. Libbey, J. Fenton, M. Thomas · obsoleted by RFC 6376 | Proposed Standard | May 2007 |
| 4870 | Domain-Based Email Authentication Using Public Keys Advertised in the DNS (DomainKeys)M. Delany · obsoleted by RFC 4871 | Historic | May 2007 |
| 4823 | FTP Transport for Secure Peer-to-Peer Business Data Interchange over the InternetT. Harding, R. Scott | Informational | April 2007 |
| 4796 | The Session Description Protocol (SDP) Content AttributeJ. Hautakorpi, G. Camarillo | Proposed Standard | February 2007 |
| 4662 | A Session Initiation Protocol (SIP) Event Notification Extension for Resource ListsA. B. Roach, B. Campbell, J. Rosenberg | Proposed Standard | August 2006 |
| 4661 | An Extensible Markup Language (XML)-Based Format for Event Notification FilteringH. Khartabil, E. Leppanen, M. Lonnfors, J. Costa-Requena | Proposed Standard | September 2006 |
| 4660 | Functional Description of Event Notification FilteringH. Khartabil, E. Leppanen, M. Lonnfors, J. Costa-Requena | Proposed Standard | September 2006 |
| 4590 | RADIUS Extension for Digest AuthenticationB. Sterman, D. Sadolevsky, D. Schwartz, D. Williams, W. Beck · obsoleted by RFC 5090 | Proposed Standard | July 2006 |
| 4572 | Connection-Oriented Media Transport over the Transport Layer Security (TLS) Protocol in the Session Description Protocol (SDP)J. Lennox · obsoleted by RFC 8122 | Proposed Standard | July 2006 |
| 4568 | Session Description Protocol (SDP) Security Descriptions for Media StreamsF. Andreasen, M. Baugher, D. Wing | Proposed Standard | July 2006 |
| 4567 | Key Management Extensions for Session Description Protocol (SDP) and Real Time Streaming Protocol (RTSP)J. Arkko, F. Lindholm, M. Naslund, K. Norrman, E. Carrara | Proposed Standard | July 2006 |
| 4504 | SIP Telephony Device Requirements and ConfigurationH. Sinnreich, Ed., S. Lass, C. Stredicke | Informational | May 2006 |
| 4490 | Using the GOST 28147-89, GOST R 34.11-94, GOST R 34.10-94, and GOST R 34.10-2001 Algorithms with Cryptographic Message Syntax (CMS)S. Leontiev, Ed., G. Chudov, Ed. | Proposed Standard | May 2006 |
| 4412 | Communications Resource Priority for the Session Initiation Protocol (SIP)H. Schulzrinne, J. Polk | Proposed Standard | February 2006 |
| 4408 | Sender Policy Framework (SPF) for Authorizing Use of Domains in E-Mail, Version 1M. Wong, W. Schlitt · obsoleted by RFC 7208 | Experimental | April 2006 |
| 4398 | Storing Certificates in the Domain Name System (DNS)S. Josefsson | Proposed Standard | March 2006 |
| 4356 | Mapping Between the Multimedia Messaging Service (MMS) and Internet MailR. Gellens | Proposed Standard | January 2006 |
| 4354 | A Session Initiation Protocol (SIP) Event Package and Data Format for Various Settings in Support for the Push-to-Talk over Cellular (PoC) ServiceM. Garcia-Martin | Informational | January 2006 |
| 4262 | X.509 Certificate Extension for Secure/Multipurpose Internet Mail Extensions (S/MIME) CapabilitiesS. Santesson | Proposed Standard | December 2005 |
| 4227 | Using the Simple Object Access Protocol (SOAP) in Blocks Extensible Exchange Protocol (BEEP)E. O'Tuathail, M. Rose | Proposed Standard | January 2006 |
| 4161 | Guidelines for Optional Services for Internet Fax GatewaysK. Mimura, K. Yokoyama, T. Satoh, K. Watanabe, C. Kanaide | Informational | September 2005 |
| 4160 | Internet Fax Gateway RequirementsK. Mimura, K. Yokoyama, T. Satoh, C. Kanaide, C. Allocchio | Informational | September 2005 |
| 4134 | Examples of S/MIME MessagesP. Hoffman, Ed. | Informational | July 2005 |
| 4130 | MIME-Based Secure Peer-to-Peer Business Data Interchange Using HTTP, Applicability Statement 2 (AS2)D. Moberg, R. Drummond | Proposed Standard | July 2005 |
| 4119 | A Presence-based GEOPRIV Location Object FormatJ. Peterson | Proposed Standard | December 2005 |
| 4073 | Protecting Multiple Contents with the Cryptographic Message Syntax (CMS)R. Housley | Proposed Standard | May 2005 |
| 4010 | Use of the SEED Encryption Algorithm in Cryptographic Message Syntax (CMS)J. Park, S. Lee, J. Kim, J. Lee | Proposed Standard | February 2005 |
| 3926 | FLUTE - File Delivery over Unidirectional TransportT. Paila, M. Luby, R. Lehtonen, V. Roca, R. Walsh · obsoleted by RFC 6726 | Experimental | October 2004 |
| 3923 | End-to-End Signing and Object Encryption for the Extensible Messaging and Presence Protocol (XMPP)P. Saint-Andre | Proposed Standard | October 2004 |
| 3911 | The Session Initiation Protocol (SIP) "Join" HeaderR. Mahy, D. Petrie | Proposed Standard | October 2004 |
| 3910 | The SPIRITS (Services in PSTN requesting Internet Services) ProtocolV. Gurbani, Ed., A. Brusilovsky, I. Faynberg, J. Gato, H. Lu, M. Unmehopa | Proposed Standard | October 2004 |
| 3903 | Session Initiation Protocol (SIP) Extension for Event State PublicationA. Niemi, Ed. | Proposed Standard | November 2004 |
| 3891 | The Session Initiation Protocol (SIP) "Replaces" HeaderR. Mahy, B. Biggs, R. Dean | Proposed Standard | September 2004 |
| 3863 | Presence Information Data Format (PIDF)H. Sugano, S. Fujimoto, G. Klyne, A. Bateman, W. Carr, J. Peterson | Proposed Standard | August 2004 |
| 3860 | Common Profile for Instant Messaging (CPIM)J. Peterson | Proposed Standard | August 2004 |
| 3859 | Common Profile for Presence (CPP)J. Peterson | Proposed Standard | August 2004 |
| 3855 | Transporting Secure/Multipurpose Internet Mail Extensions (S/MIME) Objects in X.400P. Hoffman, C. Bonatti | Proposed Standard | July 2004 |
| 3854 | Securing X.400 Content with Secure/Multipurpose Internet Mail Extensions (S/MIME)P. Hoffman, C. Bonatti, A. Eggen | Proposed Standard | July 2004 |
| 3853 | S/MIME Advanced Encryption Standard (AES) Requirement for the Session Initiation Protocol (SIP)J. Peterson | Proposed Standard | July 2004 |
| 3852 | Cryptographic Message Syntax (CMS)R. Housley · obsoleted by RFC 5652 | Proposed Standard | July 2004 |
| 3850 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1 Certificate HandlingB. Ramsdell, Ed. · obsoleted by RFC 5750 | Proposed Standard | July 2004 |