| 822 | STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGESD. Crocker · obsoleted by RFC 2822 | Internet Standard | August 1982 |
| 1847 | Security Multiparts for MIME: Multipart/Signed and Multipart/EncryptedJ. Galvin, S. Murphy, S. Crocker, N. Freed | Proposed Standard | October 1995 |
| 2045 | Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message BodiesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 2046 | Multipurpose Internet Mail Extensions (MIME) Part Two: Media TypesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 2047 | MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII TextK. Moore | Draft Standard | November 1996 |
| 2049 | Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and ExamplesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 2119 | Key words for use in RFCs to Indicate Requirement LevelsS. Bradner | Best Current Practice | March 1997 |
| 2311 | S/MIME Version 2 Message SpecificationS. Dusse, P. Hoffman, B. Ramsdell, L. Lundblade, L. Repka | Historic | March 1998 |
| 2312 | S/MIME Version 2 Certificate HandlingS. Dusse, P. Hoffman, B. Ramsdell, J. Weinstein | Historic | March 1998 |
| 2313 | PKCS #1: RSA Encryption Version 1.5B. Kaliski · obsoleted by RFC 2437 | Informational | March 1998 |
| 2314 | PKCS #10: Certification Request Syntax Version 1.5B. Kaliski · obsoleted by RFC 2986 | Informational | March 1998 |
| 2315 | PKCS #7: Cryptographic Message Syntax Version 1.5B. Kaliski | Informational | March 1998 |
| 2630 | Cryptographic Message SyntaxR. Housley · obsoleted by RFC 3369, RFC 3370 | Proposed Standard | June 1999 |
| 2631 | Diffie-Hellman Key Agreement MethodE. Rescorla | Proposed Standard | June 1999 |
| 2632 | S/MIME Version 3 Certificate HandlingB. Ramsdell, Ed. · obsoleted by RFC 3850 | Proposed Standard | June 1999 |
| 2633 | S/MIME Version 3 Message SpecificationB. Ramsdell, Ed. · obsoleted by RFC 3851 | Proposed Standard | June 1999 |
| 2634 | Enhanced Security Services for S/MIMEP. Hoffman, Ed. | Proposed Standard | June 1999 |
| 2785 | Methods for Avoiding the "Small-Subgroup" Attacks on the Diffie-Hellman Key Agreement Method for S/MIMER. Zuccherato | Informational | March 2000 |
| 3218 | Preventing the Million Message Attack on Cryptographic Message SyntaxE. Rescorla | Informational | January 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 |
| 3560 | Use of the RSAES-OAEP Key Transport Algorithm in Cryptographic Message Syntax (CMS)R. Housley | Proposed Standard | July 2003 |
| 3565 | Use of the Advanced Encryption Standard (AES) Encryption Algorithm in Cryptographic Message Syntax (CMS)J. Schaad | Proposed Standard | July 2003 |
| 3766 | Determining Strengths For Public Keys Used For Exchanging Symmetric KeysH. Orman, P. Hoffman | Best Current Practice | April 2004 |
| 3850 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1 Certificate HandlingB. Ramsdell, Ed. · obsoleted by RFC 5750 | Proposed Standard | July 2004 |
| 3851 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1 Message SpecificationB. Ramsdell, Ed. · obsoleted by RFC 5751 | Proposed Standard | July 2004 |
| 3852 | Cryptographic Message Syntax (CMS)R. Housley · obsoleted by RFC 5652 | Proposed Standard | July 2004 |
| 4056 | Use of the RSASSA-PSS Signature Algorithm in Cryptographic Message Syntax (CMS)J. Schaad | Proposed Standard | June 2005 |
| 4270 | Attacks on Cryptographic Hashes in Internet ProtocolsP. Hoffman, B. Schneier | Informational | December 2005 |
| 4288 | Media Type Specifications and Registration ProceduresN. Freed, J. Klensin · obsoleted by RFC 6838 | Best Current Practice | December 2005 |
| 4289 | Multipurpose Internet Mail Extensions (MIME) Part Four: Registration ProceduresN. Freed, J. Klensin | Best Current Practice | December 2005 |
| 5035 | Enhanced Security Services (ESS) Update: Adding CertID Algorithm AgilityJ. Schaad | Proposed Standard | August 2007 |
| 5652 | Cryptographic Message Syntax (CMS)R. Housley | Internet Standard | September 2009 |
| 5741 | RFC Streams, Headers, and BoilerplatesL. Daigle, Ed., O. Kolkman, Ed., IAB · obsoleted by RFC 7841 | Informational | December 2009 |
| 5750 | Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.2 Certificate HandlingB. Ramsdell, S. Turner · obsoleted by RFC 8550 | Proposed Standard | January 2010 |
| 5754 | Using SHA2 Algorithms with Cryptographic Message SyntaxS. Turner | Proposed Standard | January 2010 |