Algorithm Implementation Requirements and Usage Guidance for the Internet Key Exchange Protocol Version 2 (IKEv2)
RFC 8247

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Internet Engineering Task Force (IETF)                            Y. Nir
Request for Comments: 8247                                      Dell EMC
Obsoletes: 4307                                               T. Kivinen
Updates: 7296
Category: Standards Track                                     P. Wouters
ISSN: 2070-1721                                                  Red Hat
                                                              D. Migault
                                                                Ericsson
                                                          September 2017

        Algorithm Implementation Requirements and Usage Guidance
        for the Internet Key Exchange Protocol Version 2 (IKEv2)

Abstract

   The IPsec series of protocols makes use of various cryptographic
   algorithms in order to provide security services.  The Internet Key
   Exchange (IKE) protocol is used to negotiate the IPsec Security
   Association (IPsec SA) parameters, such as which algorithms should be
   used.  To ensure interoperability between different implementations,
   it is necessary to specify a set of algorithm implementation
   requirements and usage guidance to ensure that there is at least one
   algorithm that all implementations support.  This document updates
   RFC 7296 and obsoletes RFC 4307 in defining the current algorithm
   implementation requirements and usage guidance for IKEv2, and does
   minor cleaning up of the IKEv2 IANA registry.  This document does not
   update the algorithms used for packet encryption using IPsec
   Encapsulating Security Payload (ESP).

Status of This Memo

   This is an Internet Standards Track document.

   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
   Internet Standards 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/rfc8247.

Nir, et al.                  Standards Track                    [Page 1]
RFC 8247             IKEv2 Cryptographic Algorithms       September 2017

Copyright Notice

   Copyright (c) 2017 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 ....................................................2
      1.1. Conventions Used in This Document ..........................3
      1.2. Updating Algorithm Implementation Requirements and
           Usage Guidance .............................................4
      1.3. Updating Algorithm Requirement Levels ......................4
      1.4. Document Audience ..........................................5
   2. Algorithm Selection .............................................5
      2.1. Type 1 - IKEv2 Encryption Algorithm Transforms .............5
      2.2. Type 2 - IKEv2 Pseudorandom Function Transforms ............7
      2.3. Type 3 - IKEv2 Integrity Algorithm Transforms ..............8
      2.4. Type 4 - IKEv2 Diffie-Hellman Group Transforms .............9
      2.5. Summary of Changes from RFC 4307 ..........................11
   3. IKEv2 Authentication ...........................................11
      3.1. IKEv2 Authentication Method ...............................12
           3.1.1. Recommendations for RSA Key Length .................13
      3.2. Digital Signature Recommendations .........................13
   4. Algorithms for Internet of Things ..............................14
   5. Security Considerations ........................................15
   6. IANA Considerations ............................................15
   7. References .....................................................16
      7.1. Normative References ......................................16
      7.2. Informative References ....................................17
   Acknowledgements ..................................................17
   Authors' Addresses ................................................19

1.  Introduction

   The Internet Key Exchange (IKE) protocol [RFC7296] is used to
   negotiate the parameters of the IPsec SA, such as the encryption and
   authentication algorithms and the keys for the protected