Hybrid Post-Quantum Key Encapsulation Methods (PQ KEM) for Transport Layer Security 1.2 (TLS)
draft-campagna-tls-bike-sike-hybrid-03

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Internet Engineering Task Force                              M. Campagna
Internet-Draft                                               E. Crockett
Intended status: Experimental                                        AWS
Expires: September 7, 2020                                 March 6, 2020

  Hybrid Post-Quantum Key Encapsulation Methods (PQ KEM) for Transport
                        Layer Security 1.2 (TLS)
                 draft-campagna-tls-bike-sike-hybrid-03

Abstract

   Hybrid key exchange refers to executing two independent key exchanges
   and feeding the two resulting shared secrets into a Pseudo Random
   Function (PRF), with the goal of deriving a secret which is as secure
   as the stronger of the two key exchanges.  This document describes
   new hybrid key exchange schemes for the Transport Layer Security 1.2
   (TLS) protocol.  The key exchange schemes are based on combining
   Elliptic Curve Diffie-Hellman (ECDH) with a post-quantum key
   encapsulation method (PQ KEM) using the existing TLS PRF.  In
   particular, this document specifies the use of the Bit Flipping Key
   Exchange (BIKE) and Supersingular Isogeny Key Exchange (SIKE) schemes
   in combination with ECDHE as a hybrid key agreement in a TLS 1.2
   handshake.

Context

   This draft is experimental.  It is intended to define hybrid key
   exchanges in sufficient detail to allow independent experimentations
   to interoperate.  While the NIST standardization process is still a
   few years away from being complete, we know that many TLS users have
   highly sensitive workloads that would benefit from the speculative
   additional protections provided by quantum-safe key exchanges.  These
   key exchanges are likely to change through the standardization
   process.  Early experiments serve to understand the real-world
   performance characteristics of these quantum-safe schemes as well as
   provide speculative additional confidentiality assurances against a
   future adversary with a large-scale quantum computer.

   Comments are solicited and can be sent to all authors at
   mcampagna@amazon.com.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

Campagna & Crockett     Expires September 7, 2020               [Page 1]
Internet-Draft         Hybrid Key Exchange for TLS            March 2020

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   This Internet-Draft will expire on September 7, 2020.

Copyright Notice

   Copyright (c) 2020 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
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   2.  Key Exchange Algorithms . . . . . . . . . . . . . . . . . . .   4
     2.1.  Key Encapsulation Method (KEM)  . . . . . . . . . . . . .   5
     2.2.  ECDHE_[KEM] . . . . . . . . . . . . . . . . . . . . . . .   6
   3.  Hybrid Premaster Secret . . . . . . . . . . . . . . . . . . .   6
   4.  TLS Extension for Supported PQ KEM Parameters . . . . . . . .   7
   5.  Data Structures and Computations  . . . . . . . . . . . . . .   7
     5.1.  Client Hello Extensions . . . . . . . . . . . . . . . . .   8
       5.1.1.  When these extensions are sent  . . . . . . . . . . .   8
       5.1.2.  Meaning of these extensions . . . . . . . . . . . . .   8
       5.1.3.  Structure of these extensions . . . . . . . . . . . .   8
       5.1.4.  Actions of the sender . . . . . . . . . . . . . . . .   8
       5.1.5.  Actions of the receiver . . . . . . . . . . . . . . .   8
       5.1.6.  Supported PQ KEM Parameters Extension . . . . . . . .   9
     5.2.  Server Key Exchange . . . . . . . . . . . . . . . . . . .  10
       5.2.1.  When this message is sent . . . . . . . . . . . . . .  10
       5.2.2.  Meaning of this message . . . . . . . . . . . . . . .  10