Alternative Approach for Mixing Preshared Keys in IKEv2 for Post-quantum Security
draft-smyslov-ipsecme-ikev2-qr-alt-02

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Network Working Group                                         V. Smyslov
Internet-Draft                                                ELVIS-PLUS
Intended status: Standards Track                          August 3, 2020
Expires: February 4, 2021

Alternative Approach for Mixing Preshared Keys in IKEv2 for Post-quantum
                                Security
                 draft-smyslov-ipsecme-ikev2-qr-alt-02

Abstract

   An IKEv2 extension defined in [RFC8784] allows IPsec traffic to be
   protected against someone storing VPN communications today and
   decrypting it later, when (and if) quantum computers are available.
   However, this protection doesn't cover an initial IKEv2 SA, which
   might be unacceptable in some scenarios.  This specification defines
   an alternative way get the same protection against quantum computers,
   which allows to extend it on the initial IKEv2 SA.

Status of This Memo

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   This Internet-Draft will expire on February 4, 2021.

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Smyslov                 Expires February 4, 2021                [Page 1]
Internet-Draft          Alternative PPK for IKEv2            August 2020

   include Simplified BSD License text as described in Section 4.e of
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology and Notation  . . . . . . . . . . . . . . . . . .   3
   3.  Alternative Approach Description  . . . . . . . . . . . . . .   3
   4.  Computing IKE SA Keys . . . . . . . . . . . . . . . . . . . .   5
   5.  Comparison of the Conventional and the Alternative Approaches   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   The Internet Key Exchange Protocol version 2, defined in [RFC7296],
   is used in the IPsec architecture to perform authenticated key
   exchange.  [RFC8784] defines an extension of IKEv2 for protecting
   today's VPN traffic against future quantum computers.  At the time
   this extension was being developed, it was a consensus in the IPSECME
   WG that only IPsec traffic needs to have such a protection.  It was
   believed that no sensitive information is transferred over IKE SA and
   extending the protection to also cover IKE SA traffic would require
   serious modifications to core IKEv2 protocol, that contradicted to
   one of the goals to minimize such changes.  For the cases when this
   protection is needed it was suggested to immediately rekey IKE SA
   once it is created.

   In some situations it is desirable to have this protection for IKE SA
   from the very beginning, when an initial IKE SA is created.  An
   example of such situation is Group Key Management protocol using
   IKEv2, defined in [I-D.ietf-ipsecme-g-ikev2].  In this protocol
   session keys are transferred from Group Controller / Key Server
   (GCKS) to Group Members (GM) immediately once an initial IKE SA is
   created.  While it is possible to postpone transfer of the keys until
   the IKE SA is rekeyed (and [I-D.ietf-ipsecme-g-ikev2] specifies how
   to do it), the needed sequence of actions introduces an additional
   delay and adds unnecessary complexity to the protocol.

   Since [RFC8784] was written, a new IKE_INTERMEDIATE exchange for