    Network Working Group                                    D. Eastlake 3rd
    Request for Comments: 4051                         Motorola Laboratories
    Category: Standards Track                                     April 2005

          Additional XML Security Uniform Resource Identifiers (URIs)

    Status of This Memo

       This document specifies an Internet standards track protocol for the
       Internet community, and requests discussion and suggestions for
       improvements.  Please refer to the current edition of the "Internet
       Official Protocol Standards" (STD 1) for the standardization state
       and status of this protocol.  Distribution of this memo is unlimited.

    Copyright Notice

       Copyright (C) The Internet Society (2005).

    Abstract

       A number of Uniform Resource Identifiers (URIs) intended for use with
       XML Digital Signatures, Encryption, and Canonicalization are defined.
       These URIs identify algorithms and types of keying information.

    Table of Contents

       1.  Introduction..................................................  2
       2.  Algorithms....................................................  3
           2.1.  DigestMethod Algorithms.................................  3
                 2.1.1.  MD5.............................................  3
                 2.1.2.  SHA-224.........................................  3
                 2.1.3.  SHA-384.........................................  4
           2.2.  SignatureMethod Message Authentication Code Algorithms..  4
                 2.2.1.  HMAC-MD5........................................  4
                 2.2.2.  HMAC SHA Variations.............................  5
                 2.2.3.  HMAC-RIPEMD160..................................  6
           2.3.  SignatureMethod Public Key Signature Algorithms.........  6
                 2.3.1.  RSA-MD5.........................................  6
                 2.3.2.  RSA-SHA256......................................  7
                 2.3.3.  RSA-SHA384......................................  7
                 2.3.4.  RSA-SHA512......................................  7
                 2.3.5.  RSA-RIPEMD160...................................  8
                 2.3.6.  ECDSA-SHA*......................................  8
                 2.3.7.  ESIGN-SHA1......................................  8
           2.4.  Minimal Canonicalization................................  9
           2.5.  Transform Algorithms....................................  9
                 2.5.1.  XPointer........................................  9

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           2.6.  EncryptionMethod Algorithms............................. 10
                 2.6.1.  ARCFOUR Encryption Algorithm.................... 10
                 2.6.2.  Camellia Block Encryption....................... 10
                 2.6.3.  Camellia Key Wrap............................... 11
                 2.6.4.  PSEC-KEM........................................ 11
       3.  KeyInfo....................................................... 12
           3.1.  PKCS #7 Bag of Certificates and CRLs.................... 12
           3.2.  Additional RetrievalMethod Type Values.................. 12
       4.  IANA Considerations........................................... 13
       5.  Security Considerations....................................... 13
       Acknowledgements.................................................. 13
       Normative References.............................................. 13
       Informative References............................................ 15
       Author's Address.................................................. 16
       Full Copyright Statement.......................................... 17

    1.  Introduction

       XML Digital Signatures, Canonicalization, and Encryption have been
       standardized by the W3C and the joint IETF/W3C XMLDSIG working group.
       All of these are now W3C Recommendations and IETF Informational or
       Standards Track documents.  They are available as follows:

       IETF level           W3C REC     Topic
       -----------          -------     -----
       [RFC3275]  Draft Std [XMLDSIG]   XML Digital Signatures
       [RFC3076]  Info      [CANON]     Canonical XML
        - - - - - -         [XMLENC]    XML Encryption
       [RFC3741]  Info      [EXCANON]   Exclusive XML Canonicalization

       All of these standards and recommendations use URIs [RFC2396] to
       identify algorithms and keying information types.  This document
       provides a convenient reference list of URIs and descriptions for
       algorithms in which there is substantial interest, but which cannot
       or have not been included in the main documents.  Note that raising
       XML digital signature to a Draft Standard in the IETF required
       removal of any algorithms for which interoperability from the main
       standards document has not been demonstrated.  This required removal
       of the Minimal Canonicalization algorithm, in which there appears to
       be a continued interest, to be dropped from the standards track
       specification.  It is included here.

       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 [RFC2119].

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    2.  Algorithms

       The URI [RFC2396] being dropped from the standard because of the
       transition from Proposed Standard to Draft Standard is included in
       Section 2.4 with its original prefix so as to avoid changing the
       XMLDSIG standard's namespace.

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

       Additional algorithms are given URIs that start with:

          http://www.w3.org/2001/04/xmldsig-more#

       An "xmldsig-more" URI does not imply any official W3C status for
       these algorithms or identifiers or that they are only useful in
       digital signatures.  Currently, dereferencing such URIs may or may
       not produce a temporary placeholder document.  Permission to use this
       URI prefix has been given by the W3C.

    2.1.  DigestMethod Algorithms

       These algorithms are usable wherever a DigestMethod element occurs.

    2.1.1.  MD5

       Identifier:

          http://www.w3.org/2001/04/xmldsig-more#md5

       The MD5 algorithm [RFC1321] takes no explicit parameters.  An example
       of an MD5 DigestAlgorithm element is:

       <DigestAlgorithm
          Algorithm="http://www.w3.org/2001/04/xmldsig-more#md5"/>

       An MD5 digest is a 128-bit string.  The content of the DigestValue
       element shall be the base64 [RFC2405] encoding of this bit string
       viewed as a 16-octet octet stream.

    2.1.2.  SHA-224

       Identifier:
          http://www.w3.org/2001/04/xmldsig-more#sha224

       The SHA-224 algorithm [FIPS-180-2change, RFC3874] takes no explicit
       parameters.  An example of a SHA-224 DigestAlgorithm element is:

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       <DigestAlgorithm
          Algorithm="http://www.w3.org/2001/04/xmldsig-more#sha224" />

       A SHA-224 digest is a 224 bit string.  The content of the DigestValue
       element shall be the base64 [RFC2405] encoding of this string viewed
       as a 28-octet stream.  Because it takes roughly the same amount of
       effort to compute a SHA-224 message digest as a SHA-256 digest, and
       terseness is usually not a criteria in an XML application,
       consideration should be given to the use of SHA-256 as an
       alternative.

    2.1.3.  SHA-384

       Identifier:
          http://www.w3.org/2001/04/xmldsig-more#sha384

       The SHA-384 algorithm [FIPS-180-2] takes no explicit parameters.  An
       example of a SHA-384 DigestAlgorithm element is:

       <DigestAlgorithm
          Algorithm="http://www.w3.org/2001/04/xmldsig-more#sha384" />

       A SHA-384 digest is a 384 bit string.  The content of the DigestValue
       element shall be the base64 [RFC2405] encoding of this string viewed
       as a 48-octet stream.  Because it takes roughly the same amount of
       effort to compute a SHA-384 message digest as a SHA-512 digest and
       terseness is usually not a criteria in XML application, consideration
       should be given to the use of SHA-512 as an alternative.

    2.2.  SignatureMethod Message Authentication Code Algorithms

       Note: Some text in this section is duplicated from [RFC3275] for the
       convenience of the reader.  RFC 3275 is normative in case of
       conflict.

    2.2.1.  HMAC-MD5

       Identifier:
          http://www.w3.org/2001/04/xmldsig-more#hmac-md5

       The HMAC algorithm [RFC2104] 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-MD5 SignatureMethod element
       is as follows:

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       <SignatureMethod
          Algorithm="http://www.w3.org/2001/04/xmldsig-more#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 [RFC2405] encoded in the same straightforward fashion as the
       output of the digest algorithms.  For example, the SignatureValue
       element for the HMAC-MD5 digest

          9294727A 3638BB1C 13F48EF8 158BFC9D

       from the test vectors in [RFC2104] would be

          kpRyejY4uxwT9I74FYv8nQ==

       Schema Definition:

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

       DTD:

          <!ELEMENT HMACOutputLength (#PCDATA) >

       The Schema Definition and DTD immediately shown above are taken from
       [RFC3275].

       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 Variations

       Identifiers:
          http://www.w3.org/2001/04/xmldsig-more#hmac-sha224
          http://www.w3.org/2001/04/xmldsig-more#hmac-sha256
          http://www.w3.org/2001/04/xmldsig-more#hmac-sha384
          http://www.w3.org/2001/04/xmldsig-more#hmac-sha512

       SHA-224, SHA-256, SHA-384, and SHA-512 [FIPS-180-2, FIPS-180-2change,
       RFC3874] can also be used in HMAC as described in section 2.2.1 for
       HMAC-MD5.

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    2.2.3.  HMAC-RIPEMD160

       Identifier:
          http://www.w3.org/2001/04/xmldsig-more#hmac-ripemd160

       RIPEMD-160 [RIPEMD-160] can also be used in HMAC as described in
       section 2.2.1 for HMAC-MD5.

    2.3.  SignatureMethod Public Key Signature Algorithms

       These algorithms are distinguished from those in Section 2.2 in that
       they use public key methods.  The verification key is different from
       and not feasibly derivable from the signing key.

    2.3.1.  RSA-MD5

       Identifier:
          http://www.w3.org/2001/04/xmldsig-more#rsa-md5

       RSA-MD5 implies the PKCS#1 v1.5 padding algorithm described in
       [RFC3447].  An example of use is

       <SignatureMethod
          Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-md5" />

       The SignatureValue content for an RSA-MD5 signature is the base64
       [RFC2405] encoding of the octet string computed as per [RFC3447],
       section 8.1.1, signature generation for the RSASSA-PKCS1-v1_5
       signature scheme.  As specified in the EMSA-PKCS1-V1_5-ENCODE
       function in [RFC3447, section 9.2.1], the value input to the
       signature function MUST contain a pre-pended algorithm object
       identifier for the hash function, but the availability of an ASN.1
       parser and recognition of OIDs are not required of a signature
       verifier.  The PKCS#1 v1.5 representation appears as:

          CRYPT (PAD (ASN.1 (OID, DIGEST (data))))

       Note that the padded ASN.1 will be of the following form:

          01 | FF* | 00 | prefix | hash

       Vertical bar ("|") represents concatenation.  "01", "FF", and "00"
       are fixed octets of the corresponding hexadecimal value and the
       asterisk ("*") after "FF" indicates repetition.  "hash" is the MD5
       digest of the data.  "prefix" is the ASN.1 BER MD5 algorithm
       designator prefix required in PKCS #1 [RFC3447], that is:

          hex 30 20 30 0c 06 08 2a 86 48 86 f7 0d 02 05 05 00 04 10

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       This prefix is included to facilitate the use of standard
       cryptographic libraries.  The FF octet MUST be repeated enough times
       that the value of the quantity being CRYPTed is exactly one octet
       shorter than the RSA modulus.

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

    2.3.2.  RSA-SHA256

       Identifier:
          http://www.w3.org/2001/04/xmldsig-more#rsa-sha256

       This implies the PKCS#1 v1.5 padding algorithm [RFC3447] as described
       in section 2.3.1, but with the ASN.1 BER SHA-256 algorithm designator
       prefix.  An example of use is:

       <SignatureMethod
          Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256" />

    2.3.3 RSA-SHA384

       Identifier:
          http://www.w3.org/2001/04/xmldsig-more#rsa-sha384

       This implies the PKCS#1 v1.5 padding algorithm [RFC3447] as described
       in section 2.3.1, but with the ASN.1 BER SHA-384 algorithm designator
       prefix.  An example of use is:

       <SignatureMethod
          Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha384" />

       Because it takes about the same effort to calculate a SHA-384 message
       digest as a SHA-512 message digest, it is suggested that RSA-SHA512
       be used in preference to RSA-SHA384 where possible.

    2.3.4.  RSA-SHA512

       Identifier:
          http://www.w3.org/2001/04/xmldsig-more#rsa-sha512

       This implies the PKCS#1 v1.5 padding algorithm [RFC3447] as described
       in section 2.3.1, but with the ASN.1 BER SHA-512 algorithm designator
       prefix.  An example of use is:

       <SignatureMethod
          Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha512" />

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    2.3.5.  RSA-RIPEMD160

       Identifier:
         http://www.w3.org/2001/04/xmldsig-more/rsa-ripemd160

       This implies the PKCS#1 v1.5 padding algorithm [RFC3447], as
       described in section 2.3.1, but with the ASN.1 BER RIPEMD160
       algorithm designator prefix.  An example of use is:

       <SignatureMethod
         Algorithm="http://www.w3.org/2001/04/xmldsig-more/rsa-ripemd160" />

    2.3.6.  ECDSA-SHA*

       Identifiers
          http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha1
          http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha224
          http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha256
          http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha384
          http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha512

       The Elliptic Curve Digital Signature Algorithm (ECDSA) [FIPS-186-2]
       is the elliptic curve analogue of the DSA (DSS) signature method.
       For detailed specifications on how to use it with SHA hash functions
       and XML Digital Signature, please see [X9.62] and [ECDSA].

    2.3.7.  ESIGN-SHA1

       Identifier
          http://www.w3.org/2001/04/xmldsig-more#esign-sha1
          http://www.w3.org/2001/04/xmldsig-more#esign-sha224
          http://www.w3.org/2001/04/xmldsig-more#esign-sha256
          http://www.w3.org/2001/04/xmldsig-more#esign-sha384
          http://www.w3.org/2001/04/xmldsig-more#esign-sha512

       The ESIGN algorithm specified in [IEEE-P1363a] is a signature scheme
       based on the integer factorization problem.  It is much faster than
       previous digital signature schemes so ESIGN can be implemented on
       smart cards without special co-processors.

       An example of use is:

       <SignatureMethod
          Algorithm="http://www.w3.org/2001/04/xmldsig-more#esign-sha1" />

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    2.4.  Minimal Canonicalization

       Thus far two independent interoperable implementations of Minimal
       Canonicalization have not been announced.  Therefore, when XML
       Digital Signature was advanced from Proposed Standard [RFC3075] to
       Draft Standard [RFC3275], Minimal Canonicalization was dropped from
       the standards track documents.  However, there is still interest in
       Minimal Canonicalization, indicating its possible future use.  For
       its definition, see [RFC3075], Section 6.5.1.

       For reference, its identifier remains:
          http://www.w3.org/2000/09/xmldsig#minimal

    2.5.  Transform Algorithms

       Note that all CanonicalizationMethod algorithms can also be used as
       transform algorithms.

    2.5.1.  XPointer

       Identifier:
          http://www.w3.org/2001/04/xmldsig-more/xptr

       This transform algorithm takes an [XPointer] as an explicit
       parameter.  An example of use is [RFC3092]:

       <Transform
          Algorithm="http://www.w3.org/2001/04/xmldsig-more/xptr">
          <XPointer
             xmlns="http://www.w3.org/2001/04/xmldsig-more/xptr">
                xpointer(id("foo")) xmlns(bar=http://foobar.example)
                xpointer(//bar:Zab[@Id="foo"])
          </XPointer>
       </Transform>

       Schema Definition:

          <element name="XPointer" type="string">

       DTD:

          <!ELEMENT XPointer (#PCDATA) >

       Input to this transform is an octet stream (which is then parsed into
       XML).

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       Output from this transform is a node set; the results of the XPointer
       are processed as defined in the XMLDSIG specification [RFC3275] for a
       same document XPointer.

    2.6.  EncryptionMethod Algorithms

       This subsection gives identifiers and information for several
       EncryptionMethod Algorithms.

    2.6.1.  ARCFOUR Encryption Algorithm

       Identifier:
          http://www.w3.org/2001/04/xmldsig-more#arcfour

       ARCFOUR is a fast, simple stream encryption algorithm that is
       compatible with RSA Security's RC4 algorithm.  An example of the
       EncryptionMethod element using ARCFOUR is

       <EncryptionMethod
          Algorithm="http://www.w3.org/2001/04/xmldsig-more#arcfour">
          <KeySize>40</KeySize>
       </EncryptionMethod>

       Note that Arcfour makes use of the generic KeySize parameter
       specified and defined in [XMLENC].

    2.6.2.  Camellia Block Encryption

       Identifiers:
          http://www.w3.org/2001/04/xmldsig-more#camellia128-cbc
          http://www.w3.org/2001/04/xmldsig-more#camellia192-cbc
          http://www.w3.org/2001/04/xmldsig-more#camellia256-cbc

       Camellia is an efficient and secure block cipher with the same
       interface as the AES [Camellia, RFC3713], that is 128-bit block size
       and 128, 192, and 256 bit key sizes.  In XML Encryption, Camellia is
       used in the same way as the AES: It is used in the Cipher Block
       Chaining (CBC) mode with a 128-bit initialization vector (IV).  The
       resulting cipher text is prefixed by the IV.  If included in XML
       output, it is then base64 encoded.  An example Camellia
       EncryptionMethod is as follows:

       <EncryptionMethod
          Algorithm=
          "http://www.w3.org/2001/04/xmldsig-more#camellia128-cbc" />

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    2.6.3.  Camellia Key Wrap

       Identifiers:
          http://www.w3.org/2001/04/xmldsig-more#kw-camellia128
          http://www.w3.org/2001/04/xmldsig-more#kw-camellia192
          http://www.w3.org/2001/04/xmldsig-more#kw-camellia256

       The Camellia [Camellia, RFC3713] key wrap is identical to the AES key
       wrap algorithm [RFC3394] specified in the XML Encryption standard
       with "AES" replaced by "Camellia".  As with AES key wrap, the check
       value is 0xA6A6A6A6A6A6A6A6.

       The algorithm is the same regardless of the size of the Camellia key
       used in wrapping (called the key encrypting key or KEK).  The
       implementation of Camellia is OPTIONAL.  However, if it is supported,
       the same implementation guidelines of which combinations of KEK size
       and wrapped key size should be required to be supported and which are
       optional to be supported should be followed as for AES.  That is to
       say, if Camellia key wrap is supported, then wrapping 128-bit keys
       with a 128-bit KEK and wrapping 256-bit keys with a 256-bit KEK are
       REQUIRED and all other combinations are OPTIONAL.

       An example of use is:

       <EncryptionMethod
          Algorithm=
          "http://www.w3.org/2001/04/xmldsig-more#kw-camellia128" />

    2.6.4.  PSEC-KEM

       Identifier:
          http://www.w3.org/2001/04/xmldsig-more#psec-kem

       The PSEC-KEM algorithm, specified in [ISO/IEC-18033-2], is a key
       encapsulation mechanism using elliptic curve encryption.

       An example of use is:

       <EncryptionMethod
          Algorithm="http://www.w3.org/2001/04/xmlenc#psec-kem">
          <ECParameters>
             <Version>version</Version>
             <FieldID>id</FieldID>
             <Curve>curve</Curve>
             <Base>base</Base>
             <Order>order</Order>
             <Cofactor>cofactor</Cofactor>
          </ECParameters>

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       </EncryptionMethod>

       See [ISO/IEC-18033-2] for information on the parameters above.

    3.  KeyInfo

       In section 3.1 a new KeyInfo element child is specified, while in
       section 3.2 additional KeyInfo Type values for use in RetrievalMethod
       are specified.

    3.1.  PKCS #7 Bag of Certificates and CRLs

       A PKCS #7 [RFC2315] "signedData" can also be used as a bag of
       certificates and/or certificate revocation lists (CRLs).  The
       PKCS7signedData element is defined to accommodate such structures
       within KeyInfo.  The binary PKCS #7 structure is base64 [RFC2405]
       encoded.  Any signer information present is ignored.  The following
       is an example, eliding the base64 data [RFC3092]:

       <foo:PKCS7signedData
          xmlns:foo="http://www.w3.org/2001/04/xmldsig-more">
          ...
       </foo:PKCS7signedData>

    3.2.  Additional RetrievalMethod Type Values

       The Type attribute of RetrievalMethod is an optional identifier for
       the type of data to be retrieved.  The result of dereferencing a
       RetrievalMethod reference for all KeyInfo types with an XML structure
       is an XML element or document with that element as the root.  The
       various "raw" key information types return a binary value.  Thus,
       they require a Type attribute because they are not unambiguously
       parseable.

       Identifiers:
          http://www.w3.org/2001/04/xmldsig-more#KeyValue
          http://www.w3.org/2001/04/xmldsig-more#RetrievalMethod
          http://www.w3.org/2001/04/xmldsig-more#KeyName
          http://www.w3.org/2001/04/xmldsig-more#rawX509CRL
          http://www.w3.org/2001/04/xmldsig-more#rawPGPKeyPacket
          http://www.w3.org/2001/04/xmldsig-more#rawSPKISexp
          http://www.w3.org/2001/04/xmldsig-more#PKCS7signedData
          http://www.w3.org/2001/04/xmldsig-more#rawPKCS7signedData

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    4.  IANA Considerations

       As it is easy for people to construct their own unique URIs [RFC2396]
       and possibly obtain a URI from the W3C if appropriate, it is not
       intended that any additional "http://www.w3.org/2001/04/xmldsig-
       more#" URIs be created beyond those enumerated in this document.
       (W3C Namespace stability rules prohibit the creation of new URIs
       under "http://www.w3.org/2000/09/xmldsig#".)

    5.  Security Considerations

       Due to computer speed and cryptographic advances, the use of MD5 as a
       DigestMethod and the use of MD5 in the RSA-MD5 SignatureMethod is NOT
       RECOMMENDED.  The concerned cryptographic advances do not effect the
       security of HMAC-MD5; however, there is little reason not to use one
       of the SHA series of algorithms.

    Acknowledgements

       Glenn Adams, Merlin Hughs, Gregor Karlinger, Brian LaMachia, Shiho
       Moriai, Joseph Reagle, Russ Housley, and Joel Halpern.

    Normative References

       [Camellia]         "Camellia: A 128-bit Block Cipher Suitable for
                          Multiple Platforms - Design and Analysis -", K.
                          Aoki, T. Ichikawa, M. Matsui, S. Moriai, J.
                          Nakajima, T. Tokita, In Selected Areas in
                          Cryptography, 7th Annual International Workshop,
                          SAC 2000, August 2000, Proceedings, Lecture Notes
                          in Computer Science 2012, pp. 39-56, Springer-
                          Verlag, 2001.

       [ECDSA]            Blake-Wilson, S., Karlinger, G., Kobayashi, T.,
                          and Y. Wang, "Using the Elliptic Curve Signature
                          Algorithm (ECDSA) for XML Digital Signatures", RFC
                          4050, April 2005.

       [FIPS-180-2]       "Secure Hash Standard", (SHA-1/256/384/512) US
                          Federal Information Processing Standard, 1 August
                          2002.

       [FIPS-180-2change] "FIPS 180-2, Secure Hash Standard Change Notice
                          1", adds SHA-224 to [FIPS 180-2], 25 February
                          2004.

       [FIPS-186-2]       "Digital Signature Standard", National Institute
                          of Standards and Technology, 2000.

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       [IEEE-P1363a]      "Standard Specifications for Public Key
                          Cryptography:  Additional Techniques", October
                          2002.

       [ISO/IEC-18033-2]  "Information technology -- Security techniques --
                          Encryption algorithms -- Part 3: Asymmetric
                          ciphers", CD, October 2002.

       [RFC1321]          Rivest, R., "The MD5 Message-Digest Algorithm ",
                          RFC 1321, April 1992.

       [RFC2104]          Krawczyk, H., Bellare, M., and R. Canetti, "HMAC:
                          Keyed-Hashing for Message Authentication", RFC
                          2104, February 1997.

       [RFC2119]          Bradner, S., "Key words for use in RFCs to
                          Indicate Requirement Levels", BCP 14, RFC 2119,
                          March 1997.

       [RFC2396]          Berners-Lee, T., Fielding, R., and L. Masinter,
                          "Uniform Resource Identifiers (URI): Generic
                          Syntax", RFC 2396, August 1998.

       [RFC2405]          Madson, C. and N. Doraswamy, "The ESP DES-CBC
                          Cipher Algorithm With Explicit IV", RFC 2405,
                          November 1998.

       [RFC2315]          Kaliski, B., "PKCS #7: Cryptographic Message
                          Syntax Version 1.5", RFC 2315, March 1998.

       [RFC3075]          Eastlake 3rd, D., Reagle, J., and D. Solo, "XML-
                          Signature Syntax and Processing", RFC 3075, March
                          2001. (RFC 3075 was obsoleted by RFC 3275 but is
                          referenced in this document for its description of
                          Minimal Canonicalization which was dropped in RFC
                          3275.)

       [RFC3275]          Eastlake 3rd, D., Reagle, J., and D. Solo,
                          "(Extensible Markup Language) XML-Signature Syntax
                          and Processing", RFC 3275, March 2002.

       [RFC3394]          Schaad, J. and R. Housley, "Advanced Encryption
                          Standard (AES) Key Wrap Algorithm", RFC 3394,
                          September 2002.

    Eastlake 3rd                Standards Track                    [Page 14]

    RFC 4051              Additional XML Security URIs            April 2005

       [RFC3447]          Jonsson, J. and B. Kaliski, "Public-Key
                          Cryptography Standards (PKCS) #1: RSA Cryptography
                          Specifications Version 2.1", RFC 3447, February
                          2003.

       [RFC3713]          Matsui, M., Nakajima, J., and S. Moriai, "A
                          Description of the Camellia Encryption Algorithm",
                          RFC 3713, April 2004.

       [RFC3874]          Housley, R., "A 224-bit One-way Hash Function:
                          SHA-224", RFC 3874, September 2004.

       [RIPEMD-160]       ISO/IEC 10118-3:1998, "Information Technology -
                          Security techniques - Hash-functions - Part3:
                          Dedicated hash- functions", ISO, 1998.

       [X9.62]            X9.62-200X, "Public Key Cryptography for the
                          Financial Services Industry: The Elliptic Curve
                          Digital Signature Algorithm (ECDSA)", Accredited
                          Standards Committee X9, American National
                          Standards Institute.

       [XMLDSIG]          "XML-Signature Syntax and Processing", D. Eastlake
                          3rd, J. Reagle, & D. Solo, 12 February 2002.
                          <http://www.w3.org/TR/xmldsig-core/>

       [XMLENC]           "XML Encryption Syntax and Processing", J. Reagle,
                          D.  Eastlake, December 2002.
                          <http://www.w3.org/TR/2001/RED-xmlenc-core-
                          20021210/>

       [XPointer]         "XML Pointer Language (XPointer) Version 1.0", W3C
                          working draft, Steve DeRose, Eve Maler, Ron Daniel
                          Jr., January 2001.
                          <http://www.w3.org/TR/2001/WD-xptr-20010108>

    Informative References

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

       [EXCANON]          "Exclusive XML Canonicalization Version 1.0", D.
                          Eastlake, J. Reagle, 18 July 2002.
                          <http://www.w3.org/TR/REC-xml-enc-c14n-20020718/>.

       [RFC3076]          Boyer, J., "Canonical XML Version 1.0", RFC 3076,
                          March 2001.

    Eastlake 3rd                Standards Track                    [Page 15]

    RFC 4051              Additional XML Security URIs            April 2005

       [RFC3092]          Eastlake 3rd, D., Manros, C., and E. Raymond,
                          "Etymology of "Foo"", RFC 3092, 2001.

       [RFC3741]          Boyer, J., Eastlake 3rd, D., and J. Reagle,
                          "Exclusive XML Canonicalization, Version 1.0", RFC
                          3741, March 2004.

    Author's Address

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

       Phone: +1-508-786-7554 (w)
              +1-508-634-2066 (h)
       EMail: Donald.Eastlake@motorola.com

    Eastlake 3rd                Standards Track                    [Page 16]

    RFC 4051              Additional XML Security URIs            April 2005

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