| 9180 | Hybrid Public Key EncryptionR. Barnes, K. Bhargavan, B. Lipp, C. Wood | Informational | February 2022 |
| 8555 | Automatic Certificate Management Environment (ACME)R. Barnes, J. Hoffman-Andrews, D. McCarney, J. Kasten | Proposed Standard | March 2019 |
| 7468 | Textual Encodings of PKIX, PKCS, and CMS StructuresS. Josefsson, S. Leonard | Proposed Standard | April 2015 |
| 7103 | Advice for Safe Handling of Malformed MessagesM. Kucherawy, G. Shapiro, N. Freed | Informational | January 2014 |
| 5915 | Elliptic Curve Private Key StructureS. Turner, D. Brown | Informational | June 2010 |
| 4949 | Internet Security Glossary, Version 2R. Shirey | Informational | August 2007 |
| 4870 | Domain-Based Email Authentication Using Public Keys Advertised in the DNS (DomainKeys)M. Delany · obsoleted by RFC 4871 | Historic | May 2007 |
| 4716 | The Secure Shell (SSH) Public Key File FormatJ. Galbraith, R. Thayer | Informational | November 2006 |
| 4450 | Getting Rid of the Cruft: Report from an Experiment in Identifying and Reclassifying Obsolete Standards DocumentsE. Lear, H. Alvestrand | Informational | March 2006 |
| 4086 | Randomness Requirements for SecurityD. Eastlake 3rd, J. Schiller, S. Crocker | Best Current Practice | June 2005 |
| 3792 | Survey of IPv4 Addresses in Currently Deployed IETF Security Area Standards Track and Experimental DocumentsP. Nesser, II, A. Bergstrom, Ed. | Informational | June 2004 |
| 2828 | Internet Security GlossaryR. Shirey · obsoleted by RFC 4949 | Informational | May 2000 |
| 2660 | The Secure HyperText Transfer ProtocolE. Rescorla, A. Schiffman | Historic | August 1999 |
| 2626 | The Internet and the Millennium Problem (Year 2000)P. Nesser II | Informational | June 1999 |
| 2479 | Independent Data Unit Protection Generic Security Service Application Program Interface (IDUP-GSS-API)C. Adams | Informational | December 1998 |
| 2316 | Report of the IAB Security Architecture WorkshopS. Bellovin | Informational | April 1998 |
| 2315 | PKCS #7: Cryptographic Message Syntax Version 1.5B. Kaliski | Informational | March 1998 |
| 2228 | FTP Security ExtensionsM. Horowitz, S. Lunt | Proposed Standard | October 1997 |
| 2076 | Common Internet Message HeadersJ. Palme | Informational | February 1997 |
| 2049 | Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and ExamplesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 2046 | Multipurpose Internet Mail Extensions (MIME) Part Two: Media TypesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 2045 | Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message BodiesN. Freed, N. Borenstein | Draft Standard | November 1996 |
| 1895 | The Application/CALS-1840 Content-typeE. Levinson | Informational | February 1996 |
| 1875 | UNINETT PCA Policy StatementsN. Berge | Informational | December 1995 |
| 1864 | The Content-MD5 Header FieldJ. Myers, M. Rose | Draft Standard | October 1995 |
| 1848 | MIME Object Security ServicesS. Crocker, N. Freed, J. Galvin, S. Murphy | Historic | October 1995 |
| 1750 | Randomness Recommendations for SecurityD. Eastlake 3rd, S. Crocker, J. Schiller · obsoleted by RFC 4086 | Informational | December 1994 |
| 1704 | On Internet AuthenticationN. Haller, R. Atkinson | Informational | October 1994 |
| 1700 | Assigned NumbersJ. Reynolds, J. Postel · obsoleted by RFC 3232 | Historic | October 1994 |
| 1684 | Introduction to White Pages Services based on X.500P. Jurg | Informational | August 1994 |
| 1616 | X.400(1988) for the Academic and Research Community in EuropeRARE WG-MSG Task Force 88, E. Huizer, Ed., J. Romaguera, Ed. | Informational | May 1994 |
| 1544 | The Content-MD5 Header FieldM. Rose · obsoleted by RFC 1864 | Proposed Standard | November 1993 |
| 1521 | MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message BodiesN. Borenstein, N. Freed · obsoleted by RFC 2045, RFC 2046, RFC 2047, RFC 2048, RFC 2049 | Draft Standard | September 1993 |
| 1505 | Encoding Header Field for Internet MessagesA. Costanzo, D. Robinson, R. Ullmann | Experimental | August 1993 |
| 1430 | A Strategic Plan for Deploying an Internet X.500 Directory ServiceS. Hardcastle-Kille, E. Huizer, V. Cerf, R. Hobby, S. Kent | Informational | February 1993 |
| 1424 | Privacy Enhancement for Internet Electronic Mail: Part IV: Key Certification and Related ServicesB. Kaliski | Historic | February 1993 |
| 1423 | Privacy Enhancement for Internet Electronic Mail: Part III: Algorithms, Modes, and IdentifiersD. Balenson | Historic | February 1993 |
| 1422 | Privacy Enhancement for Internet Electronic Mail: Part II: Certificate-Based Key ManagementS. Kent | Historic | February 1993 |