[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits] [IPR]

Versions: (draft-lendl-enum-validation-token) 00 01 02 03 04 RFC 5105

ENUM -- Telephone Number Mapping                                O. Lendl
Working Group                                                    enum.at
Internet-Draft                                              May 08, 2007
Intended status: Informational
Expires: November 9, 2007


                ENUM Validation Token Format Definition
                  draft-ietf-enum-validation-token-03

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on November 9, 2007.

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   An ENUM domain name is tightly coupled with the underlying E.164
   number.  The process of verifying whether the Registrant of an ENUM
   domain name is identical to the Assignee of the corresponding E.164
   number is commonly called "validation".  This document describes an
   signed XML data format -- the Validation Token -- with which
   Validation Entities can convey successful completion of a validation
   procedure in a secure fashion.



Lendl                   Expires November 9, 2007                [Page 1]

Internet-Draft            ENUM Validation Token                 May 2007


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3

   2.  Data Requirements  . . . . . . . . . . . . . . . . . . . . . .  3

   3.  Digital Signature  . . . . . . . . . . . . . . . . . . . . . .  3

   4.  Field Descriptions . . . . . . . . . . . . . . . . . . . . . .  4
     4.1.  The <validation> Element . . . . . . . . . . . . . . . . .  5
     4.2.  The <tokendata> Element  . . . . . . . . . . . . . . . . .  5

   5.  Examples . . . . . . . . . . . . . . . . . . . . . . . . . . .  6
     5.1.  Unsigned Token without Registrant Information  . . . . . .  6
     5.2.  Signed token . . . . . . . . . . . . . . . . . . . . . . .  6

   6.  Formal Syntax  . . . . . . . . . . . . . . . . . . . . . . . .  9
     6.1.  Token Core Schema  . . . . . . . . . . . . . . . . . . . .  9
     6.2.  Token Data Schema  . . . . . . . . . . . . . . . . . . . . 10

   7.  Other applications of the Token concept  . . . . . . . . . . . 12

   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13

   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13

   10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14

   11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     11.1. Normative References . . . . . . . . . . . . . . . . . . . 14
     11.2. Informative References . . . . . . . . . . . . . . . . . . 15

   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 16
   Intellectual Property and Copyright Statements . . . . . . . . . . 17

















Lendl                   Expires November 9, 2007                [Page 2]

Internet-Draft            ENUM Validation Token                 May 2007


1.  Introduction

   In the case where an ENUM (E.164 Number Mapping [1]) domain name
   corresponds to an existing E.164 number [2] the delegation of this
   domain needs to be authorized by the Assignee of the corresponding
   E.164 number.  In the role model described in [15] the entity which
   performs this check is called the Validation Entity (VE).

   By conveying an ENUM Validation Token - a signed XML document - to
   the Registry a VE certifies that delegation requirements have been
   met and are current.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [3].


2.  Data Requirements

   In this model, the Token is the only piece of data passed from the VE
   to the Registry.  Therefore, the Token needs to contain as least as
   much information as the Registry requires to grant the delegation of
   the requested ENUM domain according to its registration policy.  As
   such, the Registry will need confirmation that
   o  the Token was created by an accredited VE,
   o  the Token's duration of validity conforms to the policy,
   o  the validation procedure employed has met minimum requirements as
      set forth by policy,
   o  and that the Token is protected against tampering and replay
      attacks.

   Beyond such mandatory information, the Token may optionally include
   number holder information, in particular to simplify future re-
   validations.

   For example, if initial validation requires the steps "Check the
   identity of the Registrant" and "Check the ownership of an E.164
   number" then a later revalidation only needs to re-check the
   ownership as the identity of the Registrant does not change.

   As the Token will be included (see e.g. [16]) in XML-based Registry/
   Registrar protocols like the Extensible Provisioning Protocol (EPP)
   [12] it is a natural choice to use XML to encode Validation Tokens.


3.  Digital Signature

   According to the architecture model the propriety of an ENUM



Lendl                   Expires November 9, 2007                [Page 3]

Internet-Draft            ENUM Validation Token                 May 2007


   delegation depends on the trust relationship between the Registry and
   the VE.  In general, an untrusted link between Registry and VE should
   be assumed (for instance the Token is passed along with the
   registration request by a Registrar, who might have no role in
   asserting the right-to-use).  Therefore, the Token must be protected
   against forgery, tampering and replay-attacks.

   A digital signature on the token
   o  asserts that the token was indeed generated by the indicated VE
      (authenticity)
   o  guarantees that the token was not tampered with in transit
      (integrity)
   o  enables auditing the validation process (non-repudiation).

   The cryptographic signature on the token follows RFC 3275 (XML-DSIG
   [4]).  As tokens might be transmitted as part of an already XML based
   protocol the exclusive XML canonicalization [9] MUST be used.  This
   transform guarantees that namespace declarations inherited from the
   surrounding XML do not invalidate the signature.  In order to make
   the signature an integral part of the token the "enveloped"-signature
   mode is employed.  The signature covers all information contained in
   the Token.

   XML-DSIG offers a number of cryptographic algorithms for digesting
   and signing documents and recommends SHA1/RSA-SHA1.  Recent advances
   in cryptanalysis have cast doubt on the security of SHA1 thus
   rendering this recommendation obsolete (see e.g. the Security
   Considerations of [14]).  RFC 4051 [5] defines how additional
   algorithms can be used with XML-DSIG.

   Validation Entities MUST be able to sign tokens according to XML-
   DSIG, MUST support at least SHA-256 as the digest algorithm and MUST
   be able to embed X.509 [10] certificates.  The Registry MUST define
   which signature algorithms it will accept in Validation Tokens as
   part of its local policy.

   The choice of a RSA-based signature does not require a public key
   infrastructure.  Whether the Registry acts as a certification
   authority, accepts certs from a public certification authority, or
   only accepts pre-registered keys is a local policy choice.


4.  Field Descriptions

   The Validation Token is structured into three parts: the basic
   validation information, additional information about the Registrant,
   and the digital signature.




Lendl                   Expires November 9, 2007                [Page 4]

Internet-Draft            ENUM Validation Token                 May 2007


4.1.  The <validation> Element

   A token must contain a <validation> element which contains the
   following:
   o  A single validation "serial" attribute identifying a validation
      token for a certain VE.  It must be unique per VE.
   o  A single <E164Number> element containing the underlying E.164
      number in fully qualified (international) format.
   o  An optional <lastE164Number> element.  If present it indicates
      that the whole number block starting with <E164Number> up to and
      including <lastE164Number> has been validated.  To avoid
      ambiguity, both numbers must be of the same length.
   o  A single <validationEntityID> element identifying the VE.
   o  A single <registrarID> element identifying the Registrar on whose
      behalf the validation was performed.
   o  A single <methodID> element identifying the method used by the VE
      for validation.
   o  A single <executionDate> attribute containing the date of
      validation formatted as "full-date" according to RFC 3339 [6].
   o  An optional <expirationDate> attribute marking the expiration date
      of the validation token formatted as "full-date" according to RFC
      3339.  The Registry will automatically revoke the delegation at
      this date unless a new Token has been submitted that extends the
      lifetime of the validation.  A missing expirationDate indicates
      infinite validity of the Token.

   The format and the uniqueness-constraints of these IDs is left to the
   local policy of the Registry.

4.2.  The <tokendata> Element

   A token may contain a <tokendata> section containing information
   about the number holder, consisting of the the following elements:
   o  A single <organization> element containing the full name of the
      organization to which the Registrant is affiliated.
   o  A single <commercialregisternumber> element.  If the Registrant is
      a company, then this field can be used to uniquely identify this
      company by its official registration number within the local
      country.  The interpretation of this field is thus country-
      specific.
   o  A single <title> element
   o  A single <firstname> element
   o  A single <lastname> element
   o  A single <address> section containing the following elements:
      *  A single optional <streetName>
      *  A single optional <houseNumber>





Lendl                   Expires November 9, 2007                [Page 5]

Internet-Draft            ENUM Validation Token                 May 2007


      *  A single optional <postalCode>
      *  A single optional <locality>
      *  A single optional <countyStateOrProvince>
      *  A single optional <ISOcountryCode>
   o  up to 10 <phone> elements containing full E.164 numbers
   o  up to 10 <fax> elements containing full E.164 numbers
   o  up to 10 <email> elements

   All elements directly under <tokendata> are optional.  The definition
   of the first five elements within the <address> element conforms to
   the second version of the E.115 Computerized Directory Assistance
   [17].  The <ISOcountryCode> element specifies the country using the
   ISO 3166 [11] code.


5.  Examples

5.1.  Unsigned Token without Registrant Information

   This basic Token without any information about the Registrant and
   without the cryptographic signature shows the basic layout of the
   Token.


   <?xml version="1.0" encoding="utf-8" standalone="no" ?>
   <token xmlns="urn:ietf:params:xml:ns:enum-token-1.0" Id="TOKEN"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation=
    "urn:ietf:params:xml:ns:enum-token-1.0 enum-token-1.0.xsd">
     <validation serial="acmeve-000002">
       <E164Number>+442079460200</E164Number>
       <lastE164Number>+442079460499</lastE164Number>
       <validationEntityID>ACME-VE</validationEntityID>
       <registrarID>reg-4711</registrarID>
       <methodID>42</methodID>
       <executionDate>2007-05-08</executionDate>
       <expirationDate>2007-11-01</expirationDate>
     </validation>
   </token>


5.2.  Signed token

   This example uses an X.509 based signature which includes the
   certificate of the signing validation entity.  Thus the validity of
   the signature can be verified without the need for a key-server.  A
   valid signature is a necessary, but not sufficient condition for a
   valid Token.  Any entity evaluating a Token needs to check other



Lendl                   Expires November 9, 2007                [Page 6]

Internet-Draft            ENUM Validation Token                 May 2007


   factors as well, e.g. the certificate and the XML schema.


  <?xml version="1.0" encoding="utf-8" standalone="no" ?>
  <token xmlns="urn:ietf:params:xml:ns:enum-token-1.0" Id="TOKEN"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation=
   "urn:ietf:params:xml:ns:enum-token-1.0 enum-token-1.0.xsd">
    <validation serial="acmeve-000001">
      <E164Number>+442079460123</E164Number>
      <validationEntityID>ACME-VE</validationEntityID>
      <registrarID>reg-4711</registrarID>
      <methodID>42</methodID>
      <executionDate>2007-05-08</executionDate>
    </validation>
    <tokendata xmlns="urn:ietf:params:xml:ns:enum-tokendata-1.0"
     xsi:schemaLocation=
     "urn:ietf:params:xml:ns:enum-tokendata-1.0 enum-tokendata-1.0.xsd">
      <contact>
        <organisation>Example Inc.</organisation>
        <commercialregisternumber>4711</commercialregisternumber>
        <title>Dr.</title>
        <firstname>Max</firstname>
        <lastname>Mustermann</lastname>
        <address>
          <streetName>Main</streetName>
          <houseNumber>10</houseNumber>
          <postalCode>1010</postalCode>
          <locality>London</locality>
          <countyStateOrProvince>London</countyStateOrProvince>
          <ISOcountryCode>GB</ISOcountryCode>
        </address>
        <phone>+442079460123</phone>
        <email>mm@example.com</email>
      </contact>
    </tokendata>
    <Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
      <SignedInfo>
        <CanonicalizationMethod
         Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/>
        <SignatureMethod
         Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/>
        <Reference URI="#TOKEN">
          <Transforms>
            <Transform Algorithm=
             "http://www.w3.org/2000/09/xmldsig#enveloped-signature"/>
            <Transform
             Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#">



Lendl                   Expires November 9, 2007                [Page 7]

Internet-Draft            ENUM Validation Token                 May 2007


              <InclusiveNamespaces
               xmlns="http://www.w3.org/2001/10/xml-exc-c14n#"
               PrefixList="enum-token enum-tokendata"/>
            </Transform>
          </Transforms>
          <DigestMethod
           Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/>
          <DigestValue
          >VxqsBxSNPFwPAUlCHts3g3DehcexnB1dqUz+GypLZ0k=</DigestValue>
        </Reference>
      </SignedInfo>
      <SignatureValue>
  QKqphKRNPokVZFbenje+HZZV+RLrNweGnlWBw7ngAtH+rtuslR8LhMLmC4DlBb9V
  HvKItl+7zLGm3VgYsqfHH8q3jCl1mFxUIuLlIPqtpJs+xAHAJDzZ+vmsF/q2IgrS
  K0uMmKuU5V1gydDBOvIipcJx+PrPYyXYZSjQXkWknK8=</SignatureValue>
    <KeyInfo>
  <X509Data>
  <X509Certificate>
  MIIDZjCCAs+gAwIBAgIBBDANBgkqhkiG9w0BAQQFADB0MQswCQYDVQQGEwJBVDEP
  MA0GA1UEBxMGVmllbm5hMRQwEgYDVQQKEwtCT0ZIIENlcnRzLjEbMBkGA1UEAxMS
  Q0VSVFMuYm9maC5wcml2LmF0MSEwHwYJKoZIhvcNAQkBFhJjZXJ0c0Bib2ZoLnBy
  aXYuYXQwHhcNMDQwNzIwMTMxNTA5WhcNMDUwNzIwMTMxNTA5WjB/MQswCQYDVQQG
  EwJBVDEKMAgGA1UECBMBLTEPMA0GA1UEBxMGVmllbm5hMR0wGwYDVQQKExRBY21l
  IEVOVU0gVmFsaWRhdGlvbjEQMA4GA1UEAxMHYWNtZS1WRTEiMCAGCSqGSIb3DQEJ
  ARYTbm9ib2R5QGVudW0tYWNtZS5hdDCBnzANBgkqhkiG9w0BAQEFAAOBjQAwgYkC
  gYEArJPcjMFc54/zwztSdQXGxUtodJT9r1qGI2lQPNjLvtPJg93+7o5SIOsZGSpg
  zWbztDAV5qc7PHZWUVIyf6MbM5qSgQDVrjNRhTosNtyqmwi23BH52SKkX3P7eGit
  LmqEkiUZRxZhZ6upRbtcqvKSwmXitvW4zXZhkVHYJZ2HuMcCAwEAAaOB/DCB+TAJ
  BgNVHRMEAjAAMCwGCWCGSAGG+EIBDQQfFh1PcGVuU1NMIEdlbmVyYXRlZCBDZXJ0
  aWZpY2F0ZTAdBgNVHQ4EFgQUyK4otTQtvv6KdSlMBOPT5Ve18JgwgZ4GA1UdIwSB
  ljCBk4AUvfPadpm0HhmZx2iAVumQTwgnG2eheKR2MHQxCzAJBgNVBAYTAkFUMQ8w
  DQYDVQQHEwZWaWVubmExFDASBgNVBAoTC0JPRkggQ2VydHMuMRswGQYDVQQDExJD
  RVJUUy5ib2ZoLnByaXYuYXQxITAfBgkqhkiG9w0BCQEWEmNlcnRzQGJvZmgucHJp
  di5hdIIBADANBgkqhkiG9w0BAQQFAAOBgQCB9CHBnIUhrdic4h5Ar4hdxjHSQkDH
  sJWd+MYrNcuSrv3TIOsUkUgNpNNhmkZPtiXqfy3388IRdJtJiLWXSOb/XlZHOM9I
  MvwKYwhcpQ9UdM/w7VpXQqf+CEj0XSyqxGw65UsHIOijgiG/WyhSj+Lzriw7CTge
  P2iAJkJVC4t2XA==
  </X509Certificate>
  </X509Data>
  </KeyInfo>
  </Signature>
  </token>









Lendl                   Expires November 9, 2007                [Page 8]

Internet-Draft            ENUM Validation Token                 May 2007


6.  Formal Syntax

   The formal syntax of the validation token is specified using XML
   schema notation [7] [8].  Two schemas are defined: The "token core
   schema" contains mandatory attribute definitions, the "token data
   schema" defines the format of the optional "tokendata" section.  The
   BEGIN and END tags are not part of the schema; they are used to note
   the beginning and ending of the schema for URI registration purposes.

6.1.  Token Core Schema

   BEGIN
   <?xml version="1.0" encoding="UTF-8"?>

   <schema targetNamespace="urn:ietf:params:xml:ns:enum-token-1.0"
     xmlns:enum-token="urn:ietf:params:xml:ns:enum-token-1.0"
     xmlns:enum-tokendata="urn:ietf:params:xml:ns:enum-tokendata-1.0"
     xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
     xmlns="http://www.w3.org/2001/XMLSchema"
     elementFormDefault="qualified">

   <!--  Import common element types.  -->

     <import namespace="http://www.w3.org/2000/09/xmldsig#"
             schemaLocation="xmldsig-core-schema.xsd"/>
     <import namespace="urn:ietf:params:xml:ns:enum-tokendata-1.0"
             schemaLocation="enum-tokendata-1.0.xsd"/>

     <annotation>
       <documentation>
         enum.at Validation Token core schema
       </documentation>
     </annotation>

     <element name="token" type="enum-token:tokenBaseType"/>

     <simpleType name="shortTokenType">
       <restriction base="token">
         <minLength value="1"/>
         <maxLength value="20"/>
       </restriction>
     </simpleType>

     <simpleType name="e164numberType">
       <restriction base="token">
         <maxLength value="20"/>
         <pattern value="\+\d\d*"/>
       </restriction>



Lendl                   Expires November 9, 2007                [Page 9]

Internet-Draft            ENUM Validation Token                 May 2007


     </simpleType>

     <complexType name="validationDataType">
       <sequence>
         <element name="E164Number"
                         type="enum-token:e164numberType"/>
         <element name="lastE164Number" minOccurs="0"
                         type="enum-token:e164numberType"/>
         <element name="validationEntityID"
                         type="enum-token:shortTokenType"/>
         <element name="registrarID"
                         type="enum-token:shortTokenType"/>
         <element name="methodID"
                         type="enum-token:shortTokenType"/>
         <element name="executionDate" type="date"/>
         <element name="expirationDate"
                         type="date" minOccurs="0"/>
       </sequence>
       <attribute name="serial" type="enum-token:shortTokenType"
        use="required"/>
     </complexType>

     <complexType name="tokenBaseType">
       <sequence>
         <element name="validation"
          type="enum-token:validationDataType"/>
         <any namespace="urn:ietf:params:xml:ns:enum-tokendata-1.0"
          minOccurs="0"/>
         <any namespace="http://www.w3.org/2000/09/xmldsig#"/>
       </sequence>
       <attribute name="Id" type="ID" use="required"/>
     </complexType>
   </schema>
   END


6.2.  Token Data Schema

   BEGIN
   <?xml version="1.0" encoding="UTF-8"?>

   <schema targetNamespace="urn:ietf:params:xml:ns:enum-tokendata-1.0"
     xmlns:enum-tokendata="urn:ietf:params:xml:ns:enum-tokendata-1.0"
     xmlns="http://www.w3.org/2001/XMLSchema"
     elementFormDefault="qualified">

     <element name="tokendata" type="enum-tokendata:tokenDataType"/>




Lendl                   Expires November 9, 2007               [Page 10]

Internet-Draft            ENUM Validation Token                 May 2007


     <simpleType name="E115String">
       <restriction base="string">
    <pattern value="[&#x20;-&#x7A;&#xA0;-&#xD7FF;&#xE000;-&#xFFFD;]*"/>
       </restriction>
     </simpleType>

     <simpleType name="E115StringUb256">
       <restriction base="enum-tokendata:E115String">
         <minLength value="1"/>
         <maxLength value="256"/>
       </restriction>
     </simpleType>

     <simpleType name="countryCodeType">
       <restriction base="token">
         <minLength value="2"/>
         <maxLength value="2"/>
       </restriction>
     </simpleType>

     <simpleType name="TokenType">
       <restriction base="token">
         <minLength value="1"/>
         <maxLength value="64"/>
       </restriction>
     </simpleType>

     <complexType name="addressType">
       <all>
         <element name="streetName"     minOccurs="0"
          type="enum-tokendata:E115StringUb256" />
         <element name="houseNumber"    minOccurs="0"
          type="enum-tokendata:E115StringUb256"/>
         <element name="postalCode"     minOccurs="0"
          type="enum-tokendata:E115StringUb256"/>
         <element name="locality"       minOccurs="0"
          type="enum-tokendata:E115StringUb256"/>
         <element name="countyStateOrProvince" minOccurs="0"
          type="enum-tokendata:E115StringUb256"/>
         <element name="ISOcountryCode" minOccurs="0"
          type="enum-tokendata:countryCodeType"/>
       </all>
     </complexType>

     <group name="tokenContactBaseGroup">
       <sequence>
         <element name="organisation"  minOccurs="0"
          type="enum-tokendata:E115StringUb256"/>



Lendl                   Expires November 9, 2007               [Page 11]

Internet-Draft            ENUM Validation Token                 May 2007


         <element name="commercialregisternumber" minOccurs="0"
          type="enum-tokendata:TokenType"/>
         <element name="title"         minOccurs="0"
          type="enum-tokendata:TokenType"/>
         <element name="firstname"     minOccurs="0"
          type="enum-tokendata:E115StringUb256"/>
         <element name="lastname"      minOccurs="0"
          type="enum-tokendata:E115StringUb256"/>
         <element name="address"       minOccurs="0"
          type="enum-tokendata:addressType"/>
         <element name="phone" type="enum-tokendata:TokenType"
          minOccurs="0" maxOccurs="10" />
         <element name="fax"   type="enum-tokendata:TokenType"
          minOccurs="0" maxOccurs="10" />
         <element name="email" type="enum-tokendata:TokenType"
          minOccurs="0" maxOccurs="10" />
       </sequence>
     </group>

     <complexType name="contactType">
       <sequence>
         <group ref="enum-tokendata:tokenContactBaseGroup"/>
       </sequence>
     </complexType>

     <complexType name="tokenDataType">
       <sequence>
         <element name="contact" type="enum-tokendata:contactType"/>
       </sequence>
     </complexType>

   </schema>
   END



7.  Other applications of the Token concept

   The concept of the validation token may be useful in other registry-
   type applications where the proof of an underlying right is a
   condition for a valid registration.

   An example is a TLD (Top Level Domain) where registration is subject
   to proof of some precondition, like a trade mark or the right in a
   name.  Such situations often arise during the introduction of a new
   TLD, e.g. during a "sunrise" phase.

   A Number Portability (NP) database faces very similar verification



Lendl                   Expires November 9, 2007               [Page 12]

Internet-Draft            ENUM Validation Token                 May 2007


   issues.  An NP system based on the Token concept could potentially be
   superior to current methods, and aid in the convergence of NP and
   ENUM.


8.  IANA Considerations

   This document uses URNs to describe XML namespaces and XML schemas
   conforming to a registry mechanism described in RFC 3688 [13].  Four
   URI assignments are requested.
   1.  Registration request for the Token namespace:
       *  URI: urn:ietf:params:xml:ns:enum-token-1.0
       *  Registrant Contact: See the "Author's Address" section of this
          document.
       *  XML: None.  Namespace URIs do not represent an XML
          specification.
   2.  Registration request for the Token XML schema:
       *  URI: urn:ietf:params:xml:schema:enum-token-1.0
       *  Registrant Contact: See the "Author's Address" section of this
          document.
       *  XML: See Section 6.1 of this document.
   3.  Registration request for the Token Data namespace:
       *  URI: urn:ietf:params:xml:ns:enum-tokendata-1.0
       *  Registrant Contact: See the "Author's Address" section of this
          document.
       *  XML: None.  Namespace URIs do not represent an XML
          specification.
   4.  Registration request for the Token Data XML schema:
       *  URI: urn:ietf:params:xml:schema:enum-tokendata-1.0
       *  Registrant Contact: See the "Author's Address" section of this
          document.
       *  XML: See Section 6.2 of this document.

   The IDs used in the validationEntityID, RegistrarID, and methodID
   elements are subject to local policy and thus do not require IANA
   registration.


9.  Security Considerations

   The security of the Validation Token depends on the security of the
   underlying XML DSIG algorithms.  As such, all the security
   considerations from [4] apply here as well.  Two points from there
   merit repetition:

   Transforms are used to select the relevant data for signing and to
   discard irrelevant information (e.g. pretty-printing and name-space
   local names).



Lendl                   Expires November 9, 2007               [Page 13]

Internet-Draft            ENUM Validation Token                 May 2007


   The <Reference URI="#TOKEN"> element and attribute combined with the
   Id="TOKEN" attribute in <token> specifies that the signature should
   cover the complete token.  Moving the Id="TOKEN" attribute to e.g.
   the <tokendata> element would make the signature worthless.

   It is thus critical that the Registry does not only check whether the
   Token passes a generic XML-DSIG signature check, but also that the
   signature uses approved transforms and cryptographic algorithms and
   references the <token> element as well as that the certificate
   belongs to an accredited VE.

   The Token content is not encrypted.  If local policy dictates that
   the information contained within the token should be confidential
   then this has to be handled through a different mechanism.

   When processing a delegation request the Registry must verify that
   the information contained in the Token matches the delegation
   request.  To avert replay attacks, local policy has to specify for
   how long after <executionDate> the Token can be used to authorize a
   delegation.  The <registrarID> element in the Token prevents a
   malicious second Registrar from using an eavesdropped Token to
   register a domain in his name.


10.  Acknowledgements

   The author would like to thank the following persons for their
   valuable suggestions and contributions: Michael Haberler, Alexander
   Mayrhofer, Bernie Hoeneisen, Michael Braunoeder, Staffan Hagnell,
   Lawrence Conroy, Tony Rutkowski.


11.  References

11.1.  Normative References

   [1]   Faltstrom, P. and M. Mealling, "The E.164 to Uniform Resource
         Identifiers (URI) Dynamic Delegation Discovery System (DDDS)
         Application (ENUM)", RFC 3761, April 2004.

   [2]   ITU-T, "The international public telecommunication numbering
         plan", Recommendation E.164, May 1997.

   [3]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", BCP 14, RFC 2119, March 1997.

   [4]   Eastlake, D., Reagle, J., and D. Solo, "(Extensible Markup
         Language) XML-Signature Syntax and Processing", RFC 3275,



Lendl                   Expires November 9, 2007               [Page 14]

Internet-Draft            ENUM Validation Token                 May 2007


         March 2002.

   [5]   Eastlake, D., "Additional XML Security Uniform Resource
         Identifiers (URIs)", RFC 4051, April 2005.

   [6]   Klyne, G. and C. Newman, "Date and Time on the Internet:
         Timestamps", RFC 3339, July 2002.

   [7]   Maloney, M., Beech, D., Mendelsohn, N., and H. Thompson, "XML
         Schema Part 1: Structures", W3C REC REC-xmlschema-1-20010502,
         May 2001.

   [8]   Malhotra, A. and P. Biron, "XML Schema Part 2: Datatypes", W3C
         REC REC-xmlschema-2-20010502, May 2001.

   [9]   3rd, D., Boyer, J., and J. Reagle, "Exclusive XML
         Canonicalization Version 1.0", W3C REC REC-xml-exc-c14n-
         20020718, July 2002.

   [10]  International Telecommunications Union, "Information technology
         - Open Systems Interconnection - The Directory: Public-key and
         attribute certificate frameworks", ITU-T Recommendation X.509,
         ISO Standard 9594-8, March 2000.

   [11]  International Organization for Standardization, "Codes for the
         representation of names of countries, 3rd edition",
         ISO Standard 3166, August 1988.

11.2.  Informative References

   [12]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
         RFC 3730, March 2004.

   [13]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
         January 2004.

   [14]  Schaad, J., Kaliski, B., and R. Housley, "Additional Algorithms
         and Identifiers for RSA Cryptography for use in the Internet
         X.509 Public Key Infrastructure Certificate and Certificate
         Revocation List (CRL) Profile", RFC 4055, June 2005.

   [15]  Mayrhofer, A. and B. Hoeneisen, "ENUM Validation Architecture",
         RFC 4725, November 2006.

   [16]  Hoeneisen, B., "ENUM Validation Information Mapping for the
         Extensible Provisioning  Protocol",
         draft-ietf-enum-validation-epp-03 (work in progress),
         February 2006.



Lendl                   Expires November 9, 2007               [Page 15]

Internet-Draft            ENUM Validation Token                 May 2007


   [17]  ITU-T, "Computerized Directory Assistance Version 2",
         Recommendation E.115v2, October 2005.


Author's Address

   Otmar Lendl
   enum.at GmbH
   Karlsplatz 1/2/9
   Wien  A-1010
   Austria

   Phone: +43 1 5056416 33
   Email: otmar.lendl@enum.at
   URI:   http://www.enum.at/




































Lendl                   Expires November 9, 2007               [Page 16]

Internet-Draft            ENUM Validation Token                 May 2007


Full Copyright Statement

   Copyright (C) The IETF Trust (2007).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
   THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
   THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.


Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.


Acknowledgment

   Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).





Lendl                   Expires November 9, 2007               [Page 17]


Html markup produced by rfcmarkup 1.107, available from http://tools.ietf.org/tools/rfcmarkup/