RFC 8996

Deprecating TLS 1.0 and TLS 1.1

📅 published March 2021, from ietf

RFC 8996: Deprecating TLS 1.0 and TLS 1.1 🎀

okay bestie, this one is the RFC that officially retires TLS 1.0 and TLS 1.1. It's a Best Current Practice (that's BCP 195 🫶), so it's the community's official recommended way of doing things, not just a suggestion. Here's the title block tea ☕

  • Who wrote it: K. Moriarty (CIS) and S. Farrell (Trinity College Dublin) 💅
  • When: March 2021 🌸
  • Number and status: RFC 8996, BCP 195, ISSN 2070-1721 ✨
  • What it obsoletes: RFC 5469 and RFC 7507 💀 (7507 is the version-fallback signaling cipher suite thing, more on that later)
  • What it updates: a LOT of RFCs. Like, a whole list 😭 Every one of them normatively refers to TLS 1.0 or TLS 1.1, or to DTLS 1.0, so they all get the same glow-up. The full list is:
    • 3261, 3329, 3436, 3470, 3501, 3552, 3568, 3656, 3749, 3767, 3856, 3871, 3887, 3903, 3943, 3983, 4097, 4111, 4162, 4168, 4217, 4235, 4261, 4279, 4497, 4513, 4531, 4540, 4582, 4616, 4642, 4680, 4681, 4712, 4732, 4743, 4744, 4785, 4791, 4823, 4851, 4964, 4975, 4976, 4992, 5018, 5019, 5023, 5024, 5049, 5054, 5091, 5158, 5216, 5238, 5263, 5281, 5364, 5415, 5422, 5456, 5734, 5878, 5953, 6012, 6042, 6083, 6084, 6176, 6347, 6353, 6367, 6460, 6614, 6739, 6749, 6750, 7030, 7465, 7525, 7562, 7568, 8261, 8422 🦋

Abstract 🌈

okay so this doc formally deprecates TLS 1.0 (RFC 2246) and TLS 1.1 (RFC 4346) 🔥 Both are now moved to Historic status, which is basically the retirement home for old specs 🧚 Their crypto is outdated, and lots of government and industry profiles now straight up say "avoid these old versions." TLS 1.2 became the recommended version for IETF protocols in 2008 and then TLS 1.3 came along in 2018, so everyone has had plenty of time to move on 💖

Dropping the old versions from implementations shrinks the attack surface, cuts down on misconfiguration, and makes library and product maintenance way less of a headache ✨

This doc also deprecates DTLS 1.0 (RFC 4347), but NOT DTLS 1.2 🙈 And there's no DTLS 1.1, so that's not a thing lol.

It also updates the many RFCs that normatively refer to TLS 1.0 or TLS 1.1, and it updates the TLS best practices in RFC 7525 too. That's why it's part of BCP 195 🫶

Status of This Memo 📜

This memo documents an Internet Best Current Practice 🌸

It's a product of the Internet Engineering Task Force (IETF) and represents the consensus of the IETF community 💜 It got public review and was approved for publication by the Internet Engineering Steering Group (IESG). If you want more on BCPs, check Section 2 of RFC 7841 🧚

For the current status, any errata, and how to give feedback, head to https://www.rfc-editor.org/info/rfc8996 ✨

Copyright (c) 2021 IETF Trust and the persons identified as the document authors. All rights reserved 💅

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) as they stand on the publication date. Please actually read these, because they spell out your rights and restrictions for this document 🙈 Code Components pulled out of this document must include the Simplified BSD License text, as described in Section 4.e of the Trust Legal Provisions, and they come without warranty, same as the Simplified BSD License says 🫶

Table of Contents 🦋

   1.  Introduction
     1.1.  RFCs Updated
     1.2.  Terminology
   2.  Support for Deprecation
   3.  SHA-1 Usage Problematic in TLS 1.0 and TLS 1.1
   4.  Do Not Use TLS 1.0
   5.  Do Not Use TLS 1.1
   6.  Updates to RFC 7525
   7.  Operational Considerations
   8.  Security Considerations
   9.  IANA Considerations
   10. References
     10.1.  Normative References
     10.2.  Informative References
   Acknowledgements
   Authors' Addresses

1. Introduction ✨

okay, so the history: TLS 1.0 [RFC2246] and TLS 1.1 [RFC4346] got superseded by TLS 1.2 [RFC5246] back in 2008, and TLS 1.2 has since been superseded by TLS 1.3 [RFC8446] 💖 DTLS 1.0 [RFC4347] got superseded by DTLS 1.2 [RFC6347] in 2012 🧚 So it's honestly time to deprecate TLS 1.0, TLS 1.1, and DTLS 1.0 for real. Those docs are all moved to Historic status now 🌸

Why are these versions getting the boot? Here's the tea 🔥

  • They need you to implement older cipher suites that aren't safe anymore. For example, TLS 1.0 makes TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA mandatory to implement 💀
  • They don't support current recommended cipher suites, especially AEAD ciphers (authenticated encryption with associated data), which weren't supported before TLS 1.2 🙈 Also, the old no-longer-desirable ciphersuites still have entries in the registries. Many TLS registries got updated by [RFC8447] though, which says the IETF does not recommend those entries ✨
  • The handshake's integrity depends on the SHA-1 hash 😭
  • Peer authentication depends on SHA-1 signatures 😭
  • Supporting four TLS protocol versions makes misconfiguration way more likely 💅
  • At least one widely used library plans to drop TLS 1.1 and TLS 1.0 support in upcoming releases. Products using that library would have to use older library versions to keep TLS 1.0 and TLS 1.1 working, which is clearly not it 💀

Deprecating these versions helps developers justify dropping older (D)TLS versions and moving to at least (D)TLS 1.2 🫶 It also helps product teams phase out the old stuff, which cuts down on attack surface and maintenance scope across their protocols 🦋

1.1. RFCs Updated 🎀

This document updates the following RFCs, which normatively reference TLS 1.0, TLS 1.1, or DTLS 1.0. The update makes usage of those older versions obsolete. Fallback to these versions is now prohibited 🚫 Mandatory minimum versions of TLS 1.0 or TLS 1.1 get replaced with TLS 1.2, and minimum DTLS 1.0 references get replaced with DTLS 1.2 ✨ Statements saying "TLS 1.0 is the most widely deployed version and will provide the broadest interoperability" are removed, with nothing put in their place 🙈

[RFC3261] [RFC3329] [RFC3436] [RFC3470] [RFC3501] [RFC3552] [RFC3568] [RFC3656] [RFC3749] [RFC3767] [RFC3856] [RFC3871] [RFC3887] [RFC3903] [RFC3943] [RFC3983] [RFC4097] [RFC4111] [RFC4162] [RFC4168] [RFC4217] [RFC4235] [RFC4261] [RFC4279] [RFC4497] [RFC4513] [RFC4531] [RFC4540] [RFC4582] [RFC4616] [RFC4642] [RFC4680] [RFC4681] [RFC4712] [RFC4732] [RFC4785] [RFC4791] [RFC4823] [RFC4851] [RFC4964] [RFC4975] [RFC4976] [RFC4992] [RFC5018] [RFC5019] [RFC5023] [RFC5024] [RFC5049] [RFC5054] [RFC5091] [RFC5158] [RFC5216] [RFC5238] [RFC5263] [RFC5281] [RFC5364] [RFC5415] [RFC5422] [RFC5456] [RFC5734] [RFC5878] [RFC6012] [RFC6042] [RFC6083] [RFC6084] [RFC6176] [RFC6353] [RFC6367] [RFC6739] [RFC6749] [RFC6750] [RFC7030] [RFC7465] [RFC7525] [RFC7562] [RFC7568] [RFC8261] [RFC8422]

The status of [RFC7562], [RFC6042], [RFC5456], [RFC5024], [RFC4540], and [RFC3656] will get updated, with permission from the Independent Submissions Editor 🧚

Some RFCs also normatively refer to TLS 1.0 or TLS 1.1 but have already been obsoleted. They're still listed here and marked as updated by this document, just to remind everyone that any use of the obsolete protocol should use modern TLS 💖 Those are: [RFC3316], [RFC3489], [RFC3546], [RFC3588], [RFC3734], [RFC3920], [RFC4132], [RFC4244], [RFC4347], [RFC4366], [RFC4492], [RFC4507], [RFC4572], [RFC4582], [RFC4934], [RFC5077], [RFC5081], [RFC5101], and [RFC5953].

Heads up: [RFC4642] was already updated by [RFC8143], which makes an overlapping but not quite identical update to this one 👀

[RFC6614] requires TLS 1.1 or later, even though it only makes an informative reference to [RFC4346]. That requirement gets updated to TLS 1.2 or later 💅

[RFC6460], [RFC4744], and [RFC4743] are already Historic. They're still listed and marked as updated by this document, same reason as before: any use of the obsolete protocol should use modern TLS 🌸

This document updates DTLS [RFC6347]. [RFC6347] had allowed negotiating DTLS 1.0, which is now forbidden 🚫

The DES and International Data Encryption Algorithm (IDEA) cipher suites specified in [RFC5469] got specifically removed from TLS 1.2 by [RFC5246]. Since the only TLS versions where they're defined are now Historic, [RFC5469] has been moved to Historic too 🦋

The version-fallback Signaling Cipher Suite Value from [RFC7507] was made to detect when a client and server negotiate a lower version of (D)TLS than their highest shared version. TLS 1.3 ([RFC8446]) has a different mechanism for this, using sentinel values in the ServerHello.Random field ✨ Once (D)TLS versions before 1.2 are fully deprecated, the only way to negotiate a lower version than the highest shared one would be negotiating (D)TLS 1.2 while also supporting (D)TLS 1.3. And supporting (D)TLS 1.3 already means supporting the ServerHello.Random mechanism 🧚 So the functionality from [RFC7507] is superseded, and this document marks it as Obsolete 💀

1.2. Terminology 💜

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here 🎀

2. Support for Deprecation 💅

okay so the deep dive on attacks against TLS 1.0 and TLS 1.1, plus how to mitigate them, lives in [NIST800-52r2], [RFC7457], and other RFCs referenced in those 🔍. Mitigations exist for the current known vulnerabilities ✨, but any future issues found in old protocol versions might not get mitigated in older library versions once newer libraries stop supporting those old protocols 😭. that's the lowkey scary part.

For example, NIST gave this rationale, copied with permission from Section 1.1, "History of TLS", of [NIST800-52r2]:

TLS 1.1, specified in RFC 4346 [24], was developed to address weaknesses discovered in TLS 1.0, primarily in the areas of initialization vector selection and padding error processing. Initialization vectors were made explicit to prevent a certain class of attacks on the Cipher Block Chaining (CBC) mode of operation used by TLS. The handling of padding errors was altered to treat a padding error as a bad message authentication code rather than a decryption failure. In addition, the TLS 1.1 RFC acknowledges attacks on CBC mode that rely on the time to compute the message authentication code (MAC). The TLS 1.1 specification states that to defend against such attacks, an implementation must process records in the same manner regardless of whether padding errors exist. Further implementation considerations for CBC modes (which were not included in RFC 4346 [24]) are discussed in Section 3.3.2. TLS 1.2, specified in RFC 5246 [25], made several cryptographic enhancements, particularly in the area of hash functions, with the ability to use or specify the SHA-2 family of algorithms for hash, MAC, and Pseudorandom Function (PRF) computations. TLS 1.2 also adds authenticated encryption with associated data (AEAD) cipher suites. TLS 1.3, specified in RFC 8446 [57], represents a significant change to TLS that aims to address threats that have arisen over the years. Among the changes are a new handshake protocol, a new key derivation process that uses the HMAC-based Extract-and-Expand Key Derivation Function (HKDF) [37], and the removal of cipher suites that use RSA key transport or static Diffie-Hellman ( DH) [sic] key exchanges, the CBC mode of operation, or SHA-1. Many extensions defined for use with TLS 1.2 and previous versions cannot be used with TLS 1.3.

3. SHA-1 Usage Problematic in TLS 1.0 and TLS 1.1 🚩

the integrity of both TLS 1.0 and TLS 1.1 depends on a running SHA-1 hash of the exchanged messages. that makes it possible to perform a downgrade attack on the handshake by an attacker able to perform 2^77 operations, which is well below the acceptable modern security margin 💀.

it's giving the same problem for authentication too 🙈. the handshake's authentication depends on signatures made using a SHA-1 hash, or a concatenation of MD5 and SHA-1 hashes that is not appreciably stronger than a SHA-1 hash. so an attacker who can break the severely weakened SHA-1 hash can impersonate a server.

neither TLS 1.0 nor TLS 1.1 lets the peers select a stronger hash for signatures in the ServerKeyExchange or CertificateVerify messages. so the only upgrade path is moving to a newer protocol version 🫶.

see [Bhargavan2016] for additional details 📚.

4. Do Not Use TLS 1.0 🚫

TLS 1.0 MUST NOT be used. Negotiation of TLS 1.0 from any version of TLS MUST NOT be permitted. no exceptions, bestie 😤.

any other version of TLS is more secure than TLS 1.0 🔐. while TLS 1.0 can be configured to prevent some types of interception, using the highest version available is preferred ✨.

pragmatically, clients MUST NOT send a ClientHello with ClientHello.client_version set to {03,01}. similarly, servers MUST NOT send a ServerHello with ServerHello.server_version set to {03,01}. any party receiving a Hello message with the protocol version set to {03,01} MUST respond with a "protocol_version" alert message and close the connection 💅.

historically, TLS specifications were not clear on what the record layer version number (TLSPlaintext.version) could contain when sending a ClientHello message. Appendix E of [RFC5246] notes that TLSPlaintext.version could be selected to maximize interoperability, though no definitive value is identified as ideal. that guidance is still applicable 🧚. therefore, TLS servers MUST accept any value {03,XX} (including {03,00}) as the record layer version number for ClientHello, but they MUST NOT negotiate TLS 1.0 🌸.

5. Do Not Use TLS 1.1 🚫

TLS 1.1 MUST NOT be used. Negotiation of TLS 1.1 from any version of TLS MUST NOT be permitted. same energy as TLS 1.0, periodt 💀.

pragmatically, clients MUST NOT send a ClientHello with ClientHello.client_version set to {03,02}. similarly, servers MUST NOT send a ServerHello with ServerHello.server_version set to {03,02}. any party receiving a Hello message with the protocol version set to {03,02} MUST respond with a "protocol_version" alert message and close the connection 🎀.

any newer version of TLS is more secure than TLS 1.1 🦋. while TLS 1.1 can be configured to prevent some types of interception, using the highest version available is preferred. support for TLS 1.1 is dwindling in libraries, and it will impact security going forward if mitigations for attacks cannot be easily addressed and supported in older libraries 😩.

historically, TLS specifications were not clear on what the record layer version number (TLSPlaintext.version) could contain when sending a ClientHello message. Appendix E of [RFC5246] notes that TLSPlaintext.version could be selected to maximize interoperability, though no definitive value is identified as ideal. that guidance is still applicable 🌈. therefore, TLS servers MUST accept any value {03,XX} (including {03,00}) as the record layer version number for ClientHello, but they MUST NOT negotiate TLS 1.1 ✨.

6. Updates to RFC 7525 📝

"Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)" [RFC7525] is BCP 195 🏆. it's the most recent Best Current Practice for implementing TLS, and it was based on TLS 1.2. at the time of publication, TLS 1.0 and TLS 1.1 had not yet been deprecated, so BCP 195 gets called out specifically to update the text that implements this document's deprecation recommendations 🔥.

this document updates Section 3.1.1 of [RFC7525] by changing SHOULD NOT to MUST NOT as follows:

  • Implementations MUST NOT negotiate TLS version 1.0 [RFC2246].

Rationale: TLS 1.0 (published in 1999) does not support many modern, strong cipher suites. in addition, TLS 1.0 lacks a per-record Initialization Vector (IV) for CBC-based cipher suites and does not warn against common padding errors 🥀.

  • Implementations MUST NOT negotiate TLS version 1.1 [RFC4346].

Rationale: TLS 1.1 (published in 2006) is a security improvement over TLS 1.0, but it still does not support certain stronger cipher suites 🍓.

this document updates Section 3.1.2 of [RFC7525] by changing SHOULD NOT to MUST NOT and adding a reference to RFC 6347 as follows:

  • Implementations MUST NOT negotiate DTLS version 1.0 [RFC4347] [RFC6347].

Version 1.0 of DTLS correlates to version 1.1 of TLS (see above) 💜.

7. Operational Considerations ⚙️

this document is part of BCP 195 and, as such, reflects the understanding of the IETF (at the time of this document's publication) as to the best practices for TLS and DTLS usage 🧠.

okay, real talk: TLS 1.1 has been obsolete since the publication of [RFC5246] in 2008, and DTLS 1.0 has been obsolete since the publication of [RFC6347] in 2012 🕰️. but there may still be some systems in operation that do not support (D)TLS 1.2 or higher 😬. adopting the practices recommended by this document for any systems that need to talk to that class of systems will cause failure to interoperate. however, disregarding the recommendations of this document in order to keep interoperating with that class of systems does carry some amount of risk ⚠️.

the nature of the risks incurred by operating in contravention of this document's recommendations is discussed in Sections 2 and 3. knowledge of those risks should be used, along with any potential mitigating factors and the risks inherent to updating the systems in question, when deciding how quickly to adopt the recommendations specified in this document 🫧.

8. Security Considerations 🔒

this document deprecates two older TLS protocol versions and one older DTLS protocol version, for security reasons already described 🚨. the attack surface shrinks when there are fewer supported protocols and fallback options are removed. less is literally more here 💖.

9. IANA Considerations 📋

this document has no IANA actions 🌷.

10. References 📚

10.1. Normative References

[RFC3767] Farrell, S., Ed., "Securely Available Credentials Protocol", RFC 3767, DOI 10.17487/RFC3767, June 2004, https://www.rfc-editor.org/info/rfc3767.

[RFC3856] Rosenberg, J., "A Presence Event Package for the Session Initiation Protocol (SIP)", RFC 3856, DOI 10.17487/RFC3856, August 2004, https://www.rfc-editor.org/info/rfc3856.

[RFC3871] Jones, G., Ed., "Operational Security Requirements for Large Internet Service Provider (ISP) IP Network Infrastructure", RFC 3871, DOI 10.17487/RFC3871, September 2004, https://www.rfc-editor.org/info/rfc3871.

[RFC3887] Hansen, T., "Message Tracking Query Protocol", RFC 3887, DOI 10.17487/RFC3887, September 2004, https://www.rfc-editor.org/info/rfc3887.

[RFC3903] Niemi, A., Ed., "Session Initiation Protocol (SIP) Extension for Event State Publication", RFC 3903, DOI 10.17487/RFC3903, October 2004, https://www.rfc-editor.org/info/rfc3903.

[RFC3943] Friend, R., "Transport Layer Security (TLS) Protocol Compression Using Lempel-Ziv-Stac (LZS)", RFC 3943, DOI 10.17487/RFC3943, November 2004, https://www.rfc-editor.org/info/rfc3943.

[RFC3983] Newton, A. and M. Sanz, "Using the Internet Registry Information Service (IRIS) over the Blocks Extensible Exchange Protocol (BEEP)", RFC 3983, DOI 10.17487/RFC3983, January 2005, https://www.rfc-editor.org/info/rfc3983.

[RFC4097] Barnes, M., Ed., "Middlebox Communications (MIDCOM) Protocol Evaluation", RFC 4097, DOI 10.17487/RFC4097, June 2005, https://www.rfc-editor.org/info/rfc4097.

[RFC4111] Fang, L., Ed., "Security Framework for Provider-Provisioned Virtual Private Networks (PPVPNs)", RFC 4111, DOI 10.17487/RFC4111, July 2005, https://www.rfc-editor.org/info/rfc4111.

[RFC4162] Lee, H.J., Yoon, J.H., and J.I. Lee, "Addition of SEED Cipher Suites to Transport Layer Security (TLS)", RFC 4162, DOI 10.17487/RFC4162, August 2005, https://www.rfc-editor.org/info/rfc4162.

[RFC4168] Rosenberg, J., Schulzrinne, H., and G. Camarillo, "The Stream Control Transmission Protocol (SCTP) as a Transport for the Session Initiation Protocol (SIP)", RFC 4168, DOI 10.17487/RFC4168, October 2005, https://www.rfc-editor.org/info/rfc4168.

[RFC4217] Ford-Hutchinson, P., "Securing FTP with TLS", RFC 4217, DOI 10.17487/RFC4217, October 2005, https://www.rfc-editor.org/info/rfc4217.

[RFC4235] Rosenberg, J., Schulzrinne, H., and R. Mahy, Ed., "An INVITE-Initiated Dialog Event Package for the Session Initiation Protocol (SIP)", RFC 4235, DOI 10.17487/RFC4235, November 2005, https://www.rfc-editor.org/info/rfc4235.

[RFC4261] Walker, J. and A. Kulkarni, Ed., "Common Open Policy Service (COPS) Over Transport Layer Security (TLS)", RFC 4261, DOI 10.17487/RFC4261, December 2005, https://www.rfc-editor.org/info/rfc4261.

[RFC4279] Eronen, P., Ed. and H. Tschofenig, Ed., "Pre-Shared Key Ciphersuites for Transport Layer Security (TLS)", RFC 4279, DOI 10.17487/RFC4279, December 2005, https://www.rfc-editor.org/info/rfc4279.

[RFC4346] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.1", RFC 4346, DOI 10.17487/RFC4346, April 2006, https://www.rfc-editor.org/info/rfc4346.

[RFC4497] Elwell, J., Derks, F., Mourot, P., and O. Rousseau, "Interworking between the Session Initiation Protocol (SIP) and QSIG", BCP 117, RFC 4497, DOI 10.17487/RFC4497, May 2006, https://www.rfc-editor.org/info/rfc4497.

[RFC4513] Harrison, R., Ed., "Lightweight Directory Access Protocol (LDAP): Authentication Methods and Security Mechanisms", RFC 4513, DOI 10.17487/RFC4513, June 2006, https://www.rfc-editor.org/info/rfc4513.

[RFC4531] Zeilenga, K., "Lightweight Directory Access Protocol (LDAP) Turn Operation", RFC 4531, DOI 10.17487/RFC4531, June 2006, https://www.rfc-editor.org/info/rfc4531.

[RFC4540] Stiemerling, M., Quittek, J., and C. Cadar, "NEC's Simple Middlebox Configuration (SIMCO) Protocol Version 3.0", RFC 4540, DOI 10.17487/RFC4540, May 2006, https://www.rfc-editor.org/info/rfc4540.

[RFC4582] Camarillo, G., Ott, J., and K. Drage, "The Binary Floor Control Protocol (BFCP)", RFC 4582, DOI 10.17487/RFC4582, November 2006, https://www.rfc-editor.org/info/rfc4582.

[RFC4616] Zeilenga, K., Ed., "The PLAIN Simple Authentication and Security Layer (SASL) Mechanism", RFC 4616, DOI 10.17487/RFC4616, August 2006, https://www.rfc-editor.org/info/rfc4616.

[RFC4642] Murchison, K., Vinocur, J., and C. Newman, "Using Transport Layer Security (TLS) with Network News Transfer Protocol (NNTP)", RFC 4642, DOI 10.17487/RFC4642, October 2006, https://www.rfc-editor.org/info/rfc4642.

[RFC4680] Santesson, S., "TLS Handshake Message for Supplemental Data", RFC 4680, DOI 10.17487/RFC4680, October 2006, https://www.rfc-editor.org/info/rfc4680.

[RFC4681] Santesson, S., Medvinsky, A., and J. Ball, "TLS User Mapping Extension", RFC 4681, DOI 10.17487/RFC4681, October 2006, https://www.rfc-editor.org/info/rfc4681.

[RFC4712] Siddiqui, A., Romascanu, D., Golovinsky, E., Rahman, M., and Y. Kim, "Transport Mappings for Real-time Application Quality-of-Service Monitoring (RAQMON) Protocol Data Unit (PDU)", RFC 4712, DOI 10.17487/RFC4712, October 2006, https://www.rfc-editor.org/info/rfc4712.

[RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet Denial-of-Service Considerations", RFC 4732, DOI 10.17487/RFC4732, December 2006, https://www.rfc-editor.org/info/rfc4732.

[RFC4743] Goddard, T., "Using NETCONF over the Simple Object Access Protocol (SOAP)", RFC 4743, DOI 10.17487/RFC4743, December 2006, https://www.rfc-editor.org/info/rfc4743.

[RFC4744] Lear, E. and K. Crozier, "Using the NETCONF Protocol over the Blocks Extensible Exchange Protocol (BEEP)", RFC 4744, DOI 10.17487/RFC4744, December 2006, https://www.rfc-editor.org/info/rfc4744.

[RFC4785] Blumenthal, U. and P. Goel, "Pre-Shared Key (PSK) Ciphersuites with NULL Encryption for Transport Layer Security (TLS)", RFC 4785, DOI 10.17487/RFC4785, January 2007, https://www.rfc-editor.org/info/rfc4785.

[RFC4791] Daboo, C., Desruisseaux, B., and L. Dusseault, "Calendaring Extensions to WebDAV (CalDAV)", RFC 4791, DOI 10.17487/RFC4791, March 2007, https://www.rfc-editor.org/info/rfc4791.

[RFC4823] Harding, T. and R. Scott, "FTP Transport for Secure Peer-to-Peer Business Data Interchange over the Internet", RFC 4823, DOI 10.17487/RFC4823, April 2007, https://www.rfc-editor.org/info/rfc4823.

[RFC4851] Cam-Winget, N., McGrew, D., Salowey, J., and H. Zhou, "The Flexible Authentication via Secure Tunneling Extensible Authentication Protocol Method (EAP-FAST)", RFC 4851, DOI 10.17487/RFC4851, May 2007, https://www.rfc-editor.org/info/rfc4851.

[RFC4964] Allen, A., Ed., Holm, J., and T. Hallin, "The P-Answer-State Header Extension to the Session Initiation Protocol for the Open Mobile Alliance Push to Talk over Cellular", RFC 4964, DOI 10.17487/RFC4964, September 2007, https://www.rfc-editor.org/info/rfc4964.

[RFC4975] Campbell, B., Ed., Mahy, R., Ed., and C. Jennings, Ed., "The Message Session Relay Protocol (MSRP)", RFC 4975, DOI 10.17487/RFC4975, September 2007, https://www.rfc-editor.org/info/rfc4975.

[RFC4976] Jennings, C., Mahy, R., and A. B. Roach, "Relay Extensions for the Message Sessions Relay Protocol (MSRP)", RFC 4976, DOI 10.17487/RFC4976, September 2007, https://www.rfc-editor.org/info/rfc4976.

[RFC4992] Newton, A., "XML Pipelining with Chunks for the Internet Registry Information Service", RFC 4992, DOI 10.17487/RFC4992, August 2007, https://www.rfc-editor.org/info/rfc4992.

[RFC5018] Camarillo, G., "Connection Establishment in the Binary Floor Control Protocol (BFCP)", RFC 5018, DOI 10.17487/RFC5018, September 2007, https://www.rfc-editor.org/info/rfc5018.

[RFC5019] Deacon, A. and R. Hurst, "The Lightweight Online Certificate Status Protocol (OCSP) Profile for High-Volume Environments", RFC 5019, DOI 10.17487/RFC5019, September 2007, https://www.rfc-editor.org/info/rfc5019.

[RFC5023] Gregorio, J., Ed. and B. de hOra, Ed., "The Atom Publishing Protocol", RFC 5023, DOI 10.17487/RFC5023, October 2007, https://www.rfc-editor.org/info/rfc5023.

[RFC5024] Friend, I., "ODETTE File Transfer Protocol 2.0", RFC 5024, DOI 10.17487/RFC5024, November 2007, https://www.rfc-editor.org/info/rfc5024.

[RFC5049] Bormann, C., Liu, Z., Price, R., and G. Camarillo, Ed., "Applying Signaling Compression (SigComp) to the Session Initiation Protocol (SIP)", RFC 5049, DOI 10.17487/RFC5049, December 2007, https://www.rfc-editor.org/info/rfc5049.

[RFC5054] Taylor, D., Wu, T., Mavrogiannopoulos, N., and T. Perrin, "Using the Secure Remote Password (SRP) Protocol for TLS Authentication", RFC 5054, DOI 10.17487/RFC5054, November 2007, https://www.rfc-editor.org/info/rfc5054.

[RFC5091] Boyen, X. and L. Martin, "Identity-Based Cryptography Standard (IBCS) #1: Supersingular Curve Implementations of the BF and BB1 Cryptosystems", RFC 5091, DOI 10.17487/RFC5091, December 2007, https://www.rfc-editor.org/info/rfc5091.

[RFC5158] Huston, G., "6to4 Reverse DNS Delegation Specification", RFC 5158, DOI 10.17487/RFC5158, March 2008, https://www.rfc-editor.org/info/rfc5158.

[RFC5216] Simon, D., Aboba, B., and R. Hurst, "The EAP-TLS Authentication Protocol", RFC 5216, DOI 10.17487/RFC5216, March 2008, https://www.rfc-editor.org/info/rfc5216.

[RFC5238] Phelan, T., "Datagram Transport Layer Security (DTLS) over the Datagram Congestion Control Protocol (DCCP)", RFC 5238, DOI 10.17487/RFC5238, May 2008, https://www.rfc-editor.org/info/rfc5238.

[RFC5263] Lonnfors, M., Costa-Requena, J., Leppanen, E., and H. Khartabil, "Session Initiation Protocol (SIP) Extension for Partial Notification of Presence Information", RFC 5263, DOI 10.17487/RFC5263, September 2008, https://www.rfc-editor.org/info/rfc5263.

Okay bestie, the reference list keeps going, so let's finish strong 💅✨

10.2. Informative References 📚💅

okay bestie, this is the reading list for the extra-credit stuff 🤓✨ these ones aren't required to implement the spec, but they're absolutely worth your time if you want the full story 🦋

[Bhargavan2016]
           Bhargavan, K. and G. Leuren, "Transcript Collision
           Attacks: Breaking Authentication in TLS, IKE, and SSH",
           DOI 10.14722/ndss.2016.23418, February 2016,
           <https://www.mitls.org/downloads/transcript-
           collisions.pdf>.

[NIST800-52r2]
           National Institute of Standards and Technology,
           "Guidelines for the Selection, Configuration, and Use of
           Transport Layer Security (TLS) Implementations NIST
           SP800-52r2", DOI 10.6028/NIST.SP.800-52r2, August 2019,
           <https://nvlpubs.nist.gov/nistpubs/SpecialPublications/
           NIST.SP.800-52r2.pdf>.

[RFC3316]  Arkko, J., Kuijpers, G., Soliman, H., Loughney, J., and J.
           Wiljakka, "Internet Protocol Version 6 (IPv6) for Some
           Second and Third Generation Cellular Hosts", RFC 3316,
           DOI 10.17487/RFC3316, April 2003,
           <https://www.rfc-editor.org/info/rfc3316>.

[RFC3489]  Rosenberg, J., Weinberger, J., Huitema, C., and R. Mahy,
           "STUN - Simple Traversal of User Datagram Protocol (UDP)
           Through Network Address Translators (NATs)", RFC 3489,
           DOI 10.17487/RFC3489, March 2003,
           <https://www.rfc-editor.org/info/rfc3489>.

[RFC3546]  Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J.,
           and T. Wright, "Transport Layer Security (TLS)
           Extensions", RFC 3546, DOI 10.17487/RFC3546, June 2003,
           <https://www.rfc-editor.org/info/rfc3546>.

[RFC3588]  Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.
           Arkko, "Diameter Base Protocol", RFC 3588,
           DOI 10.17487/RFC3588, September 2003,
           <https://www.rfc-editor.org/info/rfc3588>.

[RFC3734]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)
           Transport Over TCP", RFC 3734, DOI 10.17487/RFC3734, March
           2004, <https://www.rfc-editor.org/info/rfc3734>.

[RFC3920]  Saint-Andre, P., Ed., "Extensible Messaging and Presence
           Protocol (XMPP): Core", RFC 3920, DOI 10.17487/RFC3920,
           October 2004, <https://www.rfc-editor.org/info/rfc3920>.

[RFC4132]  Moriai, S., Kato, A., and M. Kanda, "Addition of Camellia
           Cipher Suites to Transport Layer Security (TLS)",
           RFC 4132, DOI 10.17487/RFC4132, July 2005,
           <https://www.rfc-editor.org/info/rfc4132>.

[RFC4244]  Barnes, M., Ed., "An Extension to the Session Initiation
           Protocol (SIP) for Request History Information", RFC 4244,
           DOI 10.17487/RFC4244, November 2005,
           <https://www.rfc-editor.org/info/rfc4244>.

[RFC4347]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
           Security", RFC 4347, DOI 10.17487/RFC4347, April 2006,
           <https://www.rfc-editor.org/info/rfc4347>.

[RFC4366]  Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J.,
           and T. Wright, "Transport Layer Security (TLS)
           Extensions", RFC 4366, DOI 10.17487/RFC4366, April 2006,
           <https://www.rfc-editor.org/info/rfc4366>.

[RFC4492]  Blake-Wilson, S., Bolyard, N., Gupta, V., Hawk, C., and B.
           Moeller, "Elliptic Curve Cryptography (ECC) Cipher Suites
           for Transport Layer Security (TLS)", RFC 4492,
           DOI 10.17487/RFC4492, May 2006,
           <https://www.rfc-editor.org/info/rfc4492>.

[RFC4507]  Salowey, J., Zhou, H., Eronen, P., and H. Tschofenig,
           "Transport Layer Security (TLS) Session Resumption without
           Server-Side State", RFC 4507, DOI 10.17487/RFC4507, May
           2006, <https://www.rfc-editor.org/info/rfc4507>.

[RFC4572]  Lennox, J., "Connection-Oriented Media Transport over the
           Transport Layer Security (TLS) Protocol in the Session
           Description Protocol (SDP)", RFC 4572,
           DOI 10.17487/RFC4572, July 2006,
           <https://www.rfc-editor.org/info/rfc4572>.

[RFC4934]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)
           Transport Over TCP", RFC 4934, DOI 10.17487/RFC4934, May
           2007, <https://www.rfc-editor.org/info/rfc4934>.

[RFC5077]  Salowey, J., Zhou, H., Eronen, P., and H. Tschofenig,
           "Transport Layer Security (TLS) Session Resumption without
           Server-Side State", RFC 5077, DOI 10.17487/RFC5077,
           January 2008, <https://www.rfc-editor.org/info/rfc5077>.

[RFC5081]  Mavrogiannopoulos, N., "Using OpenPGP Keys for Transport
           Layer Security (TLS) Authentication", RFC 5081,
           DOI 10.17487/RFC5081, November 2007,
           <https://www.rfc-editor.org/info/rfc5081>.

[RFC5101]  Claise, B., Ed., "Specification of the IP Flow Information
           Export (IPFIX) Protocol for the Exchange of IP Traffic
           Flow Information", RFC 5101, DOI 10.17487/RFC5101, January
           2008, <https://www.rfc-editor.org/info/rfc5101>.

[RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
           (TLS) Protocol Version 1.2", RFC 5246,
           DOI 10.17487/RFC5246, August 2008,
           <https://www.rfc-editor.org/info/rfc5246>.

[RFC5415]  Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley,
           Ed., "Control And Provisioning of Wireless Access Points
           (CAPWAP) Protocol Specification", RFC 5415,
           DOI 10.17487/RFC5415, March 2009,
           <https://www.rfc-editor.org/info/rfc5415>.

[RFC5456]  Spencer, M., Capouch, B., Guy, E., Ed., Miller, F., and K.
           Shumard, "IAX: Inter-Asterisk eXchange Version 2",
           RFC 5456, DOI 10.17487/RFC5456, February 2010,
           <https://www.rfc-editor.org/info/rfc5456>.

[RFC6012]  Salowey, J., Petch, T., Gerhards, R., and H. Feng,
           "Datagram Transport Layer Security (DTLS) Transport
           Mapping for Syslog", RFC 6012, DOI 10.17487/RFC6012,
           October 2010, <https://www.rfc-editor.org/info/rfc6012>.

[RFC6083]  Tuexen, M., Seggelmann, R., and E. Rescorla, "Datagram
           Transport Layer Security (DTLS) for Stream Control
           Transmission Protocol (SCTP)", RFC 6083,
           DOI 10.17487/RFC6083, January 2011,
           <https://www.rfc-editor.org/info/rfc6083>.

[RFC6084]  Fu, X., Dickmann, C., and J. Crowcroft, "General Internet
           Signaling Transport (GIST) over Stream Control
           Transmission Protocol (SCTP) and Datagram Transport Layer
           Security (DTLS)", RFC 6084, DOI 10.17487/RFC6084, January
           2011, <https://www.rfc-editor.org/info/rfc6084>.

[RFC6347]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
           Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
           January 2012, <https://www.rfc-editor.org/info/rfc6347>.

[RFC6460]  Salter, M. and R. Housley, "Suite B Profile for Transport
           Layer Security (TLS)", RFC 6460, DOI 10.17487/RFC6460,
           January 2012, <https://www.rfc-editor.org/info/rfc6460>.

[RFC6614]  Winter, S., McCauley, M., Venaas, S., and K. Wierenga,
           "Transport Layer Security (TLS) Encryption for RADIUS",
           RFC 6614, DOI 10.17487/RFC6614, May 2012,
           <https://www.rfc-editor.org/info/rfc6614>.

[RFC7457]  Sheffer, Y., Holz, R., and P. Saint-Andre, "Summarizing
           Known Attacks on Transport Layer Security (TLS) and
           Datagram TLS (DTLS)", RFC 7457, DOI 10.17487/RFC7457,
           February 2015, <https://www.rfc-editor.org/info/rfc7457>.

[RFC8143]  Elie, J., "Using Transport Layer Security (TLS) with
           Network News Transfer Protocol (NNTP)", RFC 8143,
           DOI 10.17487/RFC8143, April 2017,
           <https://www.rfc-editor.org/info/rfc8143>.

[RFC8261]  Tuexen, M., Stewart, R., Jesup, R., and S. Loreto,
           "Datagram Transport Layer Security (DTLS) Encapsulation of
           SCTP Packets", RFC 8261, DOI 10.17487/RFC8261, November
           2017, <https://www.rfc-editor.org/info/rfc8261>.

[RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
           Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
           <https://www.rfc-editor.org/info/rfc8446>.

[RFC8447]  Salowey, J. and S. Turner, "IANA Registry Updates for TLS
           and DTLS", RFC 8447, DOI 10.17487/RFC8447, August 2018,
           <https://www.rfc-editor.org/info/rfc8447>.

Acknowledgements ✨🫶

big thank-you energy to everyone who shared usage data and reviewed and/or improved this document 💖 the list goes: Michael Ackermann, David Benjamin, David Black, Deborah Brungard, Alan DeKok, Viktor Dukhovni, Julien Élie, Adrian Farrelll, Gary Gapinski, Alessandro Ghedini, Peter Gutmann, Jeremy Harris, Nick Hilliard, James Hodgkinson, Russ Housley, Hubert Kario, Benjamin Kaduk, John Klensin, Watson Ladd, Eliot Lear, Ted Lemon, John Mattsson, Keith Moore, Tom Petch, Eric Mill, Yoav Nir, Andrei Popov, Michael Richardson, Eric Rescorla, Rich Salz, Mohit Sethi, Yaron Sheffer, Rob Sayre, Robert Sparks, Barbara Stark, Martin Thomson, Sean Turner, Loganaden Velvindron, Jakub Wilk, and Christopher Wood. literally a dream team 👑🌈

Authors' Addresses 🎀

these are the humans who wrote it, and where to find them 🧚

Kathleen Moriarty
Center for Internet Security (CIS)
East Greenbush, NY
United States of America

Email: Kathleen.Moriarty.ietf@gmail.com


Stephen Farrell
Trinity College Dublin
Dublin
2
Ireland

Phone: +353-1-896-2354
Email: stephen.farrell@cs.tcd.ie
📦 where this page comes from