Transport Layer Security (TLS) Authorization Using KeyNote
RFC 6042

Document Type RFC - Informational (October 2010; No errata)
Author Angelos Keromytis 
Last updated 2015-10-14
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Independent Submission                                      A. Keromytis
Request for Comments: 6042                           Columbia University
Category: Informational                                     October 2010
ISSN: 2070-1721

       Transport Layer Security (TLS) Authorization Using KeyNote


   This document specifies the use of the KeyNote trust-management
   system as an authorization extension in the Transport Layer Security
   (TLS) Handshake Protocol, according to guidelines in RFC 5878.
   Extensions carried in the client and server hello messages confirm
   that both parties support the desired authorization data types.
   Then, if supported by both the client and the server, KeyNote
   credentials are exchanged in the supplemental data handshake message.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This is a contribution to the RFC Series, independently of any other
   RFC stream.  The RFC Editor has chosen to publish this document at
   its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at

Copyright Notice

   Copyright (c) 2010 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
   ( 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.

Keromytis                     Informational                     [Page 1]
RFC 6042             TLS Authorization Using KeyNote        October 2010

1.  Introduction

   This document describes the identifiers necessary to exchange KeyNote
   [KEYNOTE] credential assertions inside a TLS [TLS1.0] [TLS1.1]
   [TLS1.2] exchange.  Such credential assertions can authorize the
   client and/or the server to perform certain actions.  In most usage
   scenarios, the KeyNote credential assertions will be signed by a
   cryptographic public key [RFC2792].  By using the X.509 key and
   signature encoding [X509KEY], it is possible to add KeyNote-based
   authorization and policy compliance support to the existing,
   unmodified X.509 authentication exchange in TLS.

   A list of KeyNote credentials (e.g., forming a delegation chain) may
   be sent as part of the same payload.  Alternatively, a URL [RFC3986]
   pointing to the location of such a list of KeyNote credentials may be

   In most scenarios, at least one of these credentials will be issued
   to the public key of the transmitter of the credentials, i.e., said
   public key will appear in the "Licensees" field of at least one
   KeyNote credential assertion.  The same public key will generally be
   used by the transmitter of the same credentials to authenticate as
   part of the TLS exchange.  The authentication material (e.g.,
   cryptographic public key) that was used by the transmitter to
   authenticate in the TLS exchange will be provided to the KeyNote
   evaluation engine as an "Action Authorizer".

1.1.  Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC2119].

2.  KeyNote Credential Assertion Lists

   The KeyNote Assertion List type definition in the TLS Authorization
   Data Formats registry is:


   When the keynote_assertion_list value is present, the authorization
   data is a list of KeyNote credential assertions that conforms to the
   profile in RFC 2704 [KEYNOTE].

Keromytis                     Informational                     [Page 2]
RFC 6042             TLS Authorization Using KeyNote        October 2010

   A KeyNote assertion list is transmitted inside an
   AuthorizationDataEntry structure as an opaque sequence of
   1 - 2^16-1 bytes:

      opaque KeyNoteAssertionList<1..2^16-1>;

   When KeyNoteAssertionList is used, the field contains an ASCII-
   encoded list of signed KeyNote assertions, as described in RFC 2704
   [KEYNOTE].  The assertions are separated by two "\n" (newline)
   characters.  A KeyNote assertion is a structure similar to a public
   key certificate; the main difference is that instead of a binding
   between a name and a public key, KeyNote assertions bind public keys
   to authorization rules that are evaluated by the peer when the sender
   later issues specific requests.

   When making an authorization decision based on a list of KeyNote
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