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INTERNET-DRAFT                                       Donald Eastlake 3rd
                                                                Motorola
Expires: October 2001                                         April 2001



                 Additional XML Digital Signature URIs
                 ---------- --- ------- --------- ----
                  <draft-eastlake-xmldsig-uri-00.txt>



Status of This Document

   Distribution of this draft, which is intended to become an
   Informational RFC, is unlimited. Comments should be sent to the
   author or the XMLDSIG working group <w3c-ietf-xmldsig@w3.org>.

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC 2026.  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.



Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.



Abstract

   A number of algorithm URIs intended for use with XML Digital
   Signatures are defined.








D. Eastlake 3rd                                                 [Page 1]

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Table of Contents

      Status of This Document....................................1
      Copyright Notice...........................................1
      Abstract...................................................1

      Table of Contents..........................................2

      1. Introduction............................................3
      2. URIs....................................................3
      2.1 Message Digests........................................3
      2.1.1 MD5..................................................3
      2.1.2 SHA-256..............................................4
      2.1.3 SHA-512..............................................4
      2.1.4 SHA-384..............................................4
      2.2 Message Authentication Codes...........................5
      2.2.1 HMAC-MD5.............................................5
      2.2.2 HMAC-SHA-256.........................................6
      2.2.3 HMAC-SHA-512.........................................6
      2.2.4 HMAC-SHA-384.........................................6
      2.3 Signature Algorithms...................................7
      2.3.1 RSA-MD5..............................................7
      2.3.2 RSA-SHA-256..........................................7
      2.3.3 RSA-SHA-512..........................................7
      2.3.4 RSA-SHA-384..........................................7
      2.4 Canonicalizaton Algorithms.............................7
      2.4.1 Minimal Canonicalization.............................7
      2.5 Transform Algorithms...................................8
      3. IANA Considerations.....................................8
      4. Security Considerations.................................8

      References.................................................9
      Authors Addresses..........................................9

      Full Copyright Statement..................................10
      Expiration and File Name..................................10
















D. Eastlake 3rd                                                 [Page 2]

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1. Introduction

   XML Digital Signatures have been standardized by the joint IETF/W3C
   XMLDSIG working group.  The Proposed Standard is specified in [RFC
   3075].  In addition, Canonical XML, which is used by many digital
   signatures, has been standardized by the W3C and is documented in
   Informational [RFC 3076].

   [RFC 3075] specifies URIs to identify algorithms.  However, this
   ppotocol is likely to be raised to Draft Standard soon, which
   requires two independent interoperable implementations to exist.
   This may require algorithms in which there appears to be substantial
   interest to be dropped.  This document is intended as a convenient
   reference list of URIs and descriptions for any dropped from the
   Proposed Standard due to lack of implementations plus additional
   suggested algorithms in which there appears to be substantial
   interest.



2. URIs

   The sections below parallel those in Section 6 of RFC 3075 which
   group various algorithms by there use in XML Digital Sigantures.



2.1 Message Digests



2.1.1 MD5

   Identifier:
         http://md.xmldsig.ietf.arpa#md5

   The MD5 algorithm [RFC 1321] takes no explicit parameters. An example
   of an MD5 DigestAlgorithm element is:

         <DigestMethod Algorithm="http://md.xmldsig.ietf.arpa#md5"/>

   An MD5 digest is a 128-bit string. The content of the DigestValue
   element shall be the base64 [RFC 2045] encoding of this bit string
   viewed as a 16-octet octet stream.








D. Eastlake 3rd                                                 [Page 3]

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2.1.2 SHA-256

   Identifier:
         http://md.xmldsig.ietf.arpa#sha256

   The SHA-256 algorithm [SHA-256] takes no explicit parameters.  An
   example of a SHA-256 DigestAlgorithm element is:

         <DigestMethod Algorithm="http://md.xmldsig.ietf.arpa#sha256/>

   A SHA-256 disgest is a 256 bit string.  The content of the
   DigestValue element shall be the base64 [RFC 2045] encoding of this
   string viewed as a 32-octet stream.



2.1.3 SHA-512

   Identifier:
         http://md.xmldsig.ietf.arpa#sha512

   The SHA-512 algorithm [SHA-512] takes an optional truncation
   parameter, SHAtruncation, in the range 0 to 512.  An example of a
   SHA-512 DigestAlgorithm element with such a parameter is:

         <DigestMethod Algorith="http://md.xmldsig.ietf.arpa#sha512">
            <SHAtruncation>400</SHAtruncation> </DigestMethod>

   A SHA-512 digest is a 512 bit string except that, if the
   SHA512truncation parameter is present specifying truncation to n
   bits, it is the left most n bits of that string.  In effect, the
   truncation parameter defaults to 512.

   Schema Definition:

   <simpleType name="SHAtruncation">
         <restriction base="integer"/> </simpleType>

   DTD:

   <!ELEMENT SHAtruncation (#PCDATA)>



2.1.4 SHA-384

   Identifier:
         http://md.xmldsig.ietf.arpa#sha384

   The SHA-384 algorithm [SHA-384] takes an optional truncation


D. Eastlake 3rd                                                 [Page 4]

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   parameter, SHAtruncation, in the range 0 to 512.  An example of a
   SHA-384 DigestAlforithm element without such a parameter is:

         <DigestMethod Algorith="http://md.xmldsig.ietf.arpa#sha384"/>

   A SHA-384 digest is the leftmost 384 bits of the 512 bit string that
   the algorithm calculates internally except that, if the SHAtruncation
   parameter is present specifying truncation to n bits, it is the left
   most n bits of that string.  In effect, the truncation parameter
   defaults to 384. (The SHA-384 algorithm has the same internal
   structure as the SHA-512 algorithm but a few different constants are
   used, resulting in a different 512 bit hasj value, and it is normally
   truncated to 384 bits.

   See Schema Definition and DTD for SHA-512 above.



2.2 Message Authentication Codes

   Some text in this section is duplicated from RFC 3075 for the
   convenience of the reader.



2.2.1 HMAC-MD5

   Identifier:
         http://mac.xmldsig.ietf.arpa#hmac-md5

   The HMAC algorithm (RFC2104 [HMAC]) takes the truncation length in
   bits as a parameter; if the parameter is not specified then all the
   bits of the hash are output. An example of an HMAC SignatureMethod
   element:

   <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#hmac-
   md5">
      <HMACOutputLength>112</HMACOutputLength>
   </SignatureMethod>

   The output of the HMAC algorithm is ultimately the output (possibly
   truncated) of the chosen digest algorithm. This value shall be base64
   encoded in the same straightforward fashion as the output of the
   digest algorithms. Example: the SignatureValue element for the HMAC-
   MD5 digest

         9294727A 3638BB1C 13F48EF8 158BFC9D

   from the test vectors in [RFC 2104] would be



D. Eastlake 3rd                                                 [Page 5]

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         <SignatureValue>kpRyejY4uxwT9I74FYv8nQ==</SignatureValue>

   Schema Definition:

   <simpleType name="HMACOutputLengthType">
         <restriction base="integer"/> </simpleType>

   DTD:

   <!ELEMENT HMACOutputLength (#PCDATA)>

   The Schema Definition and DTD immediately above are copied from RFC
   3075.

   Although some cryptographic suspicions have recently been cast on MD5
   for use in signatures such as RSA-MD5 below, this does not effect use
   of MD5 in HMAC.



2.2.2 HMAC-SHA-256

   Identifier:
         http://mac.xmldsig.ietf.arpa#hmac-sha256

   SHA-256 [SHA-256] can also be used in HMAC as described in section
   2.2.1 above.



2.2.3 HMAC-SHA-512

   Identifier:
         http://mac.xmldsig.ietf.arpa#hmac-sha512

   SHA-512 [SHA-512] can also be used in HMAC as describe in section
   2.2.1 above.



2.2.4 HMAC-SHA-384

   Identifier:
         http://mac.xmldsig.ietf.arpa#hmac-sha384

   SHA-384 [SHA-384] can also be used in HMAC as described in section
   2.2.1 above.





D. Eastlake 3rd                                                 [Page 6]

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2.3 Signature Algorithms



2.3.1 RSA-MD5

   Identifier:
         http://sig.xmldsig.ietf.arpa#rsa-md5

   Due to increases in computer processor power and advances in
   cryptography, use of RSA-MD5 is not recommended.



2.3.2 RSA-SHA-256

   Identifier:
         http://sig.xmldsig.ietf.arpa#rsa-sha256



2.3.3 RSA-SHA-512

   Identifier:
         http://sig.xmldsig.ietf.arpa#rsa-sha512



2.3.4 RSA-SHA-384

   Identifier:
         http://sig.xmldsig.ietf.arpa#rsa-sha384



2.4 Canonicalizaton Algorithms



2.4.1 Minimal Canonicalization

   At this time there are not two independent interoperable
   implementations of Minimal Canonicalization.  Therefore, when XML
   Digital Siganture is advanced from Proposed Standard to Draft
   Standard, it must be dropped from the standard track documents.
   However, there is still substantial interest and indicates of
   possible future use for Minimal Canonicalization which can be found
   in [RFC 3075], Section 6.5.1.

   For reference, it's identifier is:


D. Eastlake 3rd                                                 [Page 7]

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         http://www.w3.org/2000/09/xmldsig#minimal



2.5 Transform Algorithms

   None included at present.

   (Java?)



3. IANA Considerations

   TBD.



4. Security Considerations

   TBD.































D. Eastlake 3rd                                                 [Page 8]

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References

   [RFC 1321] - "The MD5 Message-Digest Algorithm", R. Rivest, April
   1992.

   [RFC 2104] - "HMAC: Keyed-Hashing for Message Authentication", H.
   Krawczyk, M.  Bellare, R. Canetti, February 1997.

   [RC 2045] - "Multipurpose Internet Mail Extensions (MIME) Part One:
   Format of Internet Message Bodies", N. Freed, N. Borenstein, November
   1996.

   [RFC 3075] - "XML-Signature Syntax and Processing", D. Eastlake, J.
   Reagle, D.  Solo, March 2001.  <http://www.w3.org/TR/2000/CR-
   xmldsig-core-20001031>

   [RFC 3076] - "Canonical XML Version 1.0", J. Boyer, March 2001.
   <http://www.w3.org/TR/2001/REC-xml-c14n-20010315>

   [SHA-256] -

   [SHA-384] -

   [SHA-512] -



Authors Addresses

   Donald E. Eastlake 3rd
   Motorola
   155 Beaver Street
   Milford, MA 01757 USA

   Telephone:   +1-508-634-2066 (h)
                +1-508-261-5434 (w)
   FAX:         +1-508-261-4447 (w)
   EMail:       Donald.Eastlake@motorola.com














D. Eastlake 3rd                                                 [Page 9]

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Full Copyright Statement

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS 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.




Expiration and File Name

   This draft expires October 2001.

   Its file name is draft-eastlake-xmldsig-uri-00.txt.
















D. Eastlake 3rd                                                [Page 10]


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