Deprecating TLS 1.0 and TLS 1.1
RFC 8996

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Internet Engineering Task Force (IETF)                       K. Moriarty
Request for Comments: 8996                                           CIS
BCP: 195                                                      S. Farrell
Obsoletes: 5469, 7507                             Trinity College Dublin
Updates: 3261, 3329, 3436, 3470, 3501, 3552,                  March 2021
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Category: Best Current Practice                                         
ISSN: 2070-1721

                    Deprecating TLS 1.0 and TLS 1.1

Abstract

   This document formally deprecates Transport Layer Security (TLS)
   versions 1.0 (RFC 2246) and 1.1 (RFC 4346).  Accordingly, those
   documents have been moved to Historic status.  These versions lack
   support for current and recommended cryptographic algorithms and
   mechanisms, and various government and industry profiles of
   applications using TLS now mandate avoiding these old TLS versions.
   TLS version 1.2 became the recommended version for IETF protocols in
   2008 (subsequently being obsoleted by TLS version 1.3 in 2018),
   providing sufficient time to transition away from older versions.
   Removing support for older versions from implementations reduces the
   attack surface, reduces opportunity for misconfiguration, and
   streamlines library and product maintenance.

   This document also deprecates Datagram TLS (DTLS) version 1.0 (RFC
   4347) but not DTLS version 1.2, and there is no DTLS version 1.1.

   This document updates many RFCs that normatively refer to TLS version
   1.0 or TLS version 1.1, as described herein.  This document also
   updates the best practices for TLS usage in RFC 7525; hence, it is
   part of BCP 195.

Status of This Memo

   This memo documents an Internet Best Current Practice.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   BCPs is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8996.

Copyright Notice

   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) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

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

   Transport Layer Security (TLS) versions 1.0 [RFC2246] and 1.1
   [RFC4346] were superseded by TLS 1.2 [RFC5246] in 2008, which has now
   itself been superseded by TLS 1.3 [RFC8446].  Datagram Transport
   Layer Security (DTLS) version 1.0 [RFC4347] was superseded by DTLS
   1.2 [RFC6347] in 2012.  Therefore, it is timely to further deprecate
   TLS 1.0, TLS 1.1, and DTLS 1.0.  Accordingly, the aforementioned
   documents have been moved to Historic status.

   Technical reasons for deprecating these versions include:

   *  They require the implementation of older cipher suites that are no