SSH Agent Protocol
draft-miller-ssh-agent-02

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Internet Engineering Task Force                                D. Miller
Internet-Draft                                                   OpenSSH
Intended status: Informational                        September 30, 2017
Expires: April 3, 2018

                           SSH Agent Protocol
                       draft-miller-ssh-agent-02

Abstract

   This document describes a key agent protocol for use in the Secure
   Shell (SSH) protocol.

Status of This Memo

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   This Internet-Draft will expire on April 3, 2018.

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   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Miller                    Expires April 3, 2018                 [Page 1]
Internet-Draft                  SSH Agent                 September 2017

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Protocol Overview . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Protocol Messages . . . . . . . . . . . . . . . . . . . . . .   3
     4.1.  Generic server responses  . . . . . . . . . . . . . . . .   3
     4.2.  Adding keys to the agent  . . . . . . . . . . . . . . . .   4
       4.2.1.  DSA keys  . . . . . . . . . . . . . . . . . . . . . .   4
       4.2.2.  ECDSA keys  . . . . . . . . . . . . . . . . . . . . .   5
       4.2.3.  ED25519 keys  . . . . . . . . . . . . . . . . . . . .   5
       4.2.4.  RSA keys  . . . . . . . . . . . . . . . . . . . . . .   6
       4.2.5.  Adding keys from a token  . . . . . . . . . . . . . .   6
       4.2.6.  Key Constraints . . . . . . . . . . . . . . . . . . .   7
         4.2.6.1.  Key lifetime constraint . . . . . . . . . . . . .   7
         4.2.6.2.  Key confirmation constraint . . . . . . . . . . .   8
         4.2.6.3.  Constraint extensions . . . . . . . . . . . . . .   8
     4.3.  Removing keys from the agent  . . . . . . . . . . . . . .   8
     4.4.  Requesting a list of keys . . . . . . . . . . . . . . . .   9
     4.5.  Private key operations  . . . . . . . . . . . . . . . . .   9
       4.5.1.  Signature flags . . . . . . . . . . . . . . . . . . .  10
     4.6.  Locking and unlocking an agent  . . . . . . . . . . . . .  10
     4.7.  Extension mechanism . . . . . . . . . . . . . . . . . . .  11
       4.7.1.  Query extension . . . . . . . . . . . . . . . . . . .  11
   5.  Protocol numbers  . . . . . . . . . . . . . . . . . . . . . .  11
     5.1.  Message numbers . . . . . . . . . . . . . . . . . . . . .  12
       5.1.1.  Reserved message numbers  . . . . . . . . . . . . . .  12
     5.2.  Constraint identifiers  . . . . . . . . . . . . . . . . .  12
     5.3.  Signature flags . . . . . . . . . . . . . . . . . . . . .  13
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  13
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
     7.1.  New registry: SSH agent protocol numbers  . . . . . . . .  13
     7.2.  New registry: SSH agent key constraint numbers  . . . . .  14
     7.3.  New registry: SSH agent signature flags . . . . . . . . .  15
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  15
   9.  Normative References  . . . . . . . . . . . . . . . . . . . .  16
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  17

1.  Introduction

   Secure Shell (SSH) is a protocol for secure remote connections and
   login over untrusted networks.  It supports multiple authentication
   mechanisms, including public key authentication.  This document
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