Copyright © 1999 The Internet Society & W3C (MIT, INRIA, Keio), All Rights Reserved. W3C liability, trademark, document use and software licensing rules apply.
Done - JR.
This document includes updates from the 991001 based on email discussion and the results of 991007 teleconference (and any resulting email discussion). The goal is to get some version of this document out as an ietf-draft and W3C technical report as soon as possible.
This is the first (and rough) public draft of this specification. This draft
covers most of the topics the final specification will cover, however parts of the text
and syntax within this specification are subject to change.
Please send comments to the editor <reagle@w3.org>
and cc: the list <w3c-ietf-xmldsig@w3.org>.
Publication as a Working Draft does not imply endorsement by the W3C membership or IESG.
This is a draft document and may be updated, replaced or obsoleted by other documents at
any time. It is inappropriate to cite W3C Drafts as other than "work in
progress". A list of current W3C working drafts can be found at http://www.w3.org/TR
Patent disclosures relevant to this specification may be found on the WG's patent disclosure page.
; Will activate/tweak the above text when we move forward. - JR.
This document specified the core signature syntax and processing rules.
...
This document describes the proposed syntax and processing rules for the XML Digital Signature specification. This specification provides a mechanism for applying digital signatures to XML documents and other Internet resources.
The structure allows for both embedded and detached signatures. An embedded signature can include the signature within the signed object or embed the signed object within the signature. A detached signature allows the signature to be independent of the object. The processing structure allows for switching between embedded and detached signatures without invalidating the signature.
In addition to the basic signature document type, this document also defines other useful types including a methods of referencing multiple resources and key management and algorithm definitions.
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].
The XML namespace [XML-namespace] URI that MUST be used by experimental implementations of this dated specification is:
xmlns="http://www.w3.org/1999/10/signature-core"
While applications MUST support XML-namespaces, the use of our "dsig" XML namespace prefix and defaulting/scoping conventions are OPTIONAL -- we use these facilities so as to provide compact and readable examples.
The URI in the namespace declaration above is also used as a prefix for URIs which
identify resources, algorithms, or semantics under control of this specification. We use
MIME types to identify algorithithms, resources, or their characteristics under the
control of IANA. Otherwise we define a URN Namespace Identifier [RFC2141].
for other organizations, for example: urn:ietf-org:hmac-sha1
EDITORIAL COMMENT: This mixed use of identification requires further thought as it is confusing as presently specified and used. The WG has not taken any steps to register the "urn:dsig" namespace.
This document includes the following abbreviations for long words. (The acronyms are generated by wrapping the word_length-2 in the first and last letter):
Finally, this document may include editorial comments (highlighted in a light tan wit a blue border) that point out open issues the WG has not yet closed. Readers unfamiliar with DTD syntax may wish to refer to Ron Bourret's "Declaring Elements and Attributes in an XML DTD."
The design philosophy and requirements of this specification are addressed in the XML-Signature Requirements document [XML-Signature-RD]. However, a few of the key philosphy axioms are repeated. This specification endeavors to rely upon the syntax -- and the underlying data model -- to represent the functionality and structure of a signature where ever possible. One way this is manifested is by the use URIs to define the relationships between a signature and its context (its constituent parts, the objects it signs, the algorithms it employs, etc.). This philosophy is best captured by the idea that of "if you make statements about statements, signature is merely one type of statement " This allows us to clearly (and perhaps formally) define the meaning of a signature and how that meaning interacts with the semantics of the content it signs. One way this is manifested is in the choice of the WG to avoid things like:
<attribute type="CDATA" and value="CDATA"/>
Instead, if applications need to associate external semantics for key exchange or trust processing they must introduce a set of qualified namespace [XML-namespace] application elements with clearly defined semantics, or they must make a statement about an existing resource within some data model.
; insert eastlake's proposal? - JR.
The general structure of an XML signature includes the following elements:
SignedInfo is the actual data over which the signature is calculated. It
contains control information (algorithm identifiers, pre-processing transformations) and
digest(s) over the object(s) being signed. SignatureValue is an empty-element tag [XML] that contains the actual value of the digital signature. KeyInfo is an optional element which enables the recipient(s) to obtain the
key(s) needed to validate the signature. Object is an optional element wherein applications may place (embed)
content through use of the XML-namespace facility. [XML-namespace]
<!ELEMENT Signature (SignedInfo, SignatureValue, KeyInfo?,
Object*)>
<!ATTLIST SignedInfo
Id ID
#IMPLIED>
A simple example follows:
<Signature
xmlns="http://www.w3.org/1999/10/signature-core">
<SignedInfo>
<CanonicalizationAlg Algorithm="null"/>
<SignatureAlg algorithm="dsig:rsaWithSHA-1"/>
<ObjectReference>
<Location HREF="http://www.iet.org"/>
<Type>text/html;
charset="us-ascii"</Type>
<DigestAlg Algorithm="sha-1"/>
<DigestValue Value="a23bcd43" />
</ObjectReference>
</SignedInfo>
<SignatureValue
encoding="urn:dsig:base64">dd2323dd</SignatureValue>
<KeyInfo>
<keyname>Solo</keyname>
</keyinfo>
</Signature>
SignatureValue The SignatureValue element contains the actual value of the digital
signature. The ability to define a SignatureAlg and SignatureValue
pair which includes multiple distinct signatures is explicitly permitted (e.g.
"rsawithsha-1 and ecdsawithsha-1").
<!ELEMENT SignatureValue CDATA)>
<!-- base64 encoded signature value -->
<!ATTLIST SignatureValue
encoding CDATA
"urn:dsig:base64">
; need base64 reference. -JR..
SignedInfo The structure of SignedInfo includes a canonicalizatin algorithm, a
signature algorithm, and one or more references to objects. The SignedInfo
element may contain an optional ID attribute that will allow it to be referenced by other
signatures and objects.
<!ELEMENT SignedInfo(CanonicalizationAlg?, SignatureAlg,
ObjectReference+ )>
<!ATTLIST SignedInfo
Id ID
#IMPLIED>
SignedInfo does not include explicit signature attributes (in the
traditional cryptographic sense). If an application needs to associate semantics (such as
signing time, signing device, etc.) with the signature, it may add an additional Object
that includes those semantics and reference that Object via an ObjectReference.
CanonicalizationAlg (Canonicalization) CanonicalizationAlg is an optional element which specifies the
canonicalization (CanonicalizationAlg) algorithm applied to the SignedInfo
element prior to performing signature calculations. This element uses the general
structure here for algorithms in which an URI is included as an attribute naming the
algorithm and optional contents of the element contain any parameter, value, or other
information defined by the algorithm name. Possible options may include a null algorithm
(no changes), a simple identity algorithm (CRLF and charset normalization), or more
extensive operations such as [XML-C14N].
<!ELEMENT CanonicalizationAlg ANY>
<!ATTLIST CanonicalizationAlg
Algorithm CDATA
"null">
<!-- Where CDATA conforms to the
productions specified by [URI]
-->
SignatureAlg SignatureAlg is a required element which specifies the algorithm used for
signature generation and validation. This algorithm ID identifies all cryptographic
functions involved in the signature operation (e.g. hashing, public key algorithms, MACs,
etc.). This element uses the general structure here for algorithms in which a URI is
included as an attribute naming the algorithm and optional contents of the element contain
any parameter, value, or other information defined by the algorithm name. While there is a
single identifier, that identifier may specify a format containing multiple distinct
signature values.
<!ELEMENT SignatureAlg ANY>
<!ATTLIST SignatureAlg
Algorithm CDATA
#REQUIRED >
<!-- Where CDATA conforms to the
productions specified by [URI]
-->
ObjectReference ObjectReference is an element that may occur one or more times. It
includes a URI, the type of the object, specified transformations, a digest algorith and
digest value. Note, it is the content yielded after the URI is dereferenced, decoded, and
transformed that the digest algorithm is applied to.
<!ELEMENT ObjectReference (Location?, Type?, Transformations?, DigestAlg, DigestValue) >
Location Location identifies where to find the Object . This element
may be omitted if the location is implicit in the application.
; Solo clarify? - Jr.
<!ELEMENT Location EMPTY >
<!ATTLIST Location
HREF
CDATA #IMPLIED >
<!-- Where CDATA conforms to the
productions specified by [URI]
-->
Type Type is an optional element which contains information about the type of
object being signed (e.g. manifest, package, document, SignedInfo, PDF file).
This may be represented as a name (e.g. MIME type), or URI.
<!ELEMENT Type (ANY | #PCDATA) >
<!-- where PCDATA conforms to the productions specified for the
content of a Content-Type MIME header
[RFC 2045] or is
a namespace qualified element name -->
Type is an optional element which contains information about the type of
object being signed (e.g. manifest, package, document, SignedInfo, PDF file).
This may be represented as a name (e.g. MIME type), or URI. For example:
<Type>text/plain; charset="us-ascii"</Type>
<Type>http://www.w3.org/1999/10/signature-core/manifest</Type>
<Type>urn:ietf-org:hmac-sha1</Type>
Transformations Transformations is an optional element that contains one or more (ordered)
operations to be performed on the Object prior to signature calculation.
Examples of Transformations include encoding, canonicalization, XPointer,
XSLT, filtering, encoding, etc. (These operations are different from those specified in
the signature; those are only applied over signedinfo.)
Each element within Transformations uses the general structure here for
algorithms in which a URI is included as a value specifying the algorithm and optional
contents of the element contain any parameter, value, or other information defined by the
algorithm name. If the Transformations element is omitted, the only operation
performed is the default object CanonicalizationAlg algorithm (null or identity).
Note that when transformations are applied the signer is not signing the native (original) document but the resulting (transformed) document that is not captured explicitly in the signature syntax. Where transformation processes are well known and widely implemented an application might include native content and specify transformations by reference. Otherwise, an application may perform transformations on the content itself and use the resulting content within the signature.
<!ELEMENT Transformations (Generic | CanonicalizationAlg | Encoding
| XSLT Stylesheet | XPointer)*)
>
<!ELEMENT Generic EMPTY >
<!ATTLIST Generic
Algorithm CDATA
#REQUIRED >
<!-- While not necessary because of the Generic, we
define a few specific transformation types.
<!ELEMENT Encoding EMPTY >
<!ATTLIST Encoding
Algorithm CDATA
#REQUIRED >
<!ELEMENT CanonicalizationAlg EMPTY >
<!ATTLIST CanonicalizationAlg
Algorithm CDATA
#REQUIRED >
<!ELEMENT XSLT EMPTY >
<!ATTLIST XSLT
Algorithm CDATA
#REQUIRED >
<!ELEMENT Stylesheet EMPTY >
<!ATTLIST Stylesheet
Algorithm CDATA
#REQUIRED >
<!ELEMENT XPointer EMPTY >
<!ATTLIST XPointer
Algorithm CDATA
#REQUIRED >
<!-- Where CDATA conforms to the
productions specified by [URI]
-->
DigestAlg DigestAlg is a required element which identifies the digest algorithm to
be applied to the signed object. This element uses the general structure here for
algorithms in which a URI is included as an attribute naming the algorithm and optional
contents of the element contain any parameter, value, or other information defined by the
algorithm name.
<!ELEMENT DigestAlg ANY>
<!ATTLIST DigestAlg
Algorithm
CDATA #REQUIRED >
<!-- Where CDATA conforms to the
productions specified by [URI]
-->
digestvalue digestvalue is an element which contains the base64 encoded value of the
digest.
<!ELEMENT DigestValue CDATA>
<!-- base64 encoded digest value -->
Object When present this element may contain any item and specifies the encoding. It is
important to note that the content of the Object itself is not part of the
hash algorithm over the signature.
<!ELEMENT Object ANY>
<!ATTLIST Object
Id CDATA
#IMPLIED
Type CDATA
#IMPLIED
Encoding
CDATA #IMPLIED >
<!-- Where type and encoding CDATA conforms to the
productions specified by [URI]
-->
; Define what is meant by type, define the types. Also, do we allow duplication in reference and object? Does the reference type refer to the type of the Object tag, which will always be XML. Don should tweak. -JR
Object is an optional element which may occur one or more times. The
purpose of Object element is to wrap elements defined by any XML application
as introduced through the namespace [XML-namespace] facility.
For instance, the following Object references a timestamp document that is
defined by some other specification.
<Object id="timestamp1"
Type="signatureattributes" > ;need to define this type
<timestamp xmlsn="http://www.ietf.org/rfc/1234">
<date>19990908</date>
<time>14:34:34:34</time>
</timestamp>
</Object>
The Object's ID is referenced from the ObjectReference in SignedInfo.
This element is used for embedded signatures where the object being signed is to be
included in the signature document. The Object element may include optional
type, ID, and encoding attributes. Note there is nothing that prevents these other XML
applications from referencing and making statements about signatures.
KeyInfo KeyInfo may contain keys, names, certificates and other public key
management information (such as inband key distribution or agreement data or use any other
method.) This specification defines a few simple types but applications may place
(embed) their own key identification and exchange semantics within this element through
the XML-namespace facility. [XML-namespace]
; is adding PCDATA the writing thing to do?
<!ELEMENT KeyInfo (#PCDATA | (KeyName | KeyValue
|
SubjectName | RetrievalMethod |
x509Data |
PGPData | MgmtData)* )>
KeyInfo is an optional element which enables the recipient(s) to obtain
the key(s) needed to validate the signature. If omitted, the recipient is expected to be
able to identify the key based on application context information. This element contains
one or more KeyInfo data elements providing information for the recipient(s).
Applications may define and use any mechanism they choose through inclusion of elements
from a different namespace.
KeyName contains an identifier for the key which may be useful to the
recipient. This may be a name, index, etc. KeyValue contains the actual key(s) used to validate the signature. If the
key is sent in protected form, the MgmtData element should be used. Specific
types must be defined for each algorithm type (see algorithms). SubjectName contains one or more names for the sender. Forms to be
supported include a simple name string, encoded DN, email address, etc. RetrievalMethod is a URI which may be used to obtain key and/or certificate
information. The URI should contain the complete string for retrieving the key needed for
this message (rather than a generic URI). X509Data contains an identifier of the key/cert used for validation (either
an issuerserial value, a subject name, or a subjectkeyID) and an optional collection of
certificates and revocation/status information which may be used by the recipient.
issuerserial contains the encoded issuer name (RFCxxxx) along with the serial number. PGPData data associated with a PGP key. MgmtData contains in-band key distribution or agreement data. Examples may
include DH key exchange, RSA key encryption etc. <!ELEMENT KeyName (#PCDATA)>
<!ELEMENT KeyValue (#PCDATA)>
<!ELEMENT SubjectName (#PCDATA)>
<!ELEMENT RetrievalMethod (#PCDATA)>
<!ELEMENT X509Data (#PCDATA)>
<!ELEMENT MgmtData (#PCDATA)>
; this is very unspecified, should add note. - JR.
This sections identifies algorithms used with the XML digital signature standard. Entries contain the identifier to be used in signature documents, a reference to the formal specification, and definitions, where applicable, for the representation of keys and the results of cryptographic operations.
The specification defines a set of algorithms, their URNs, and requirements for implementation. Requirements are specified over implementation, not over requirements for signature use. Furthermore, the mechanism is extensible, alternative algorithms may be used by signature applications.
| Algorithm Type | Algorithm | Requirements | Algorithm URI | URN Derivation |
| Digest | ||||
| SHA1 | REQUIRED | urn:nist-gov:sha1 | IOTP | |
| MAC | ||||
| HMAC-SHA1 | REQUIRED | urn:ietf-org:hmac-sha1 | extrapolated from IOTP | |
| HMAC-MD5 | OPTIONAL | urn:ietf-org:hmac-md5 ; remove this too? | extrapolated from IOTP | |
| Signature | ||||
| DSAwithSHA1 (DSS) | REQUIRED | urn:nist-gov:dsa | IOTP | |
| RSAwithSHA1 | RECOMMENDED | urn:rsasdi-com:rsa-sha1 | extrapolated from IOTP | |
| RSAwithMD5 | OPTIONAL | urn:rsasdi-com:rsa-md5 ; remove this too? | extrapolated from IOTP | |
| ECDSA | OPTIONAL | urn:nist-gov:ecdsa ; David, find ANSI reference | extrapolated from IOTP | |
| Canonicalization | ||||
| :null | REQUIRED | http://www.w3.org/1999/10/signature-core/null | suggested W3C | |
| :minimal | REQUIRED | http://www.w3.org/1999/10/signature-core/minimal | suggested W3C | |
| XML-Canonicalization | RECOMMENDED | http://www.w3.org/1999/07/WD-xml-CanonicalizationAlg-19990729 | W3C | |
| DOM-Canonicalization | RECOMMENDED | urn:ietf-org:dom-xml-canonicalization | suggested | |
| Transformation | ||||
| XPath/XLST | RECOMMENDED | http://www.w3.org/1999/07/WD-xptr-19990709 | W3C |
The SHA-1 algorithm identifier is urn:nist-gov:sha1. The SHA-1 algorithm takes no parameters. An example of an SHA-1 DigestAlg element is
<DigestAlg Algorithm="urn:nist-gov:sha1"/>
An SHA-1 digest is a 160-bit string. The content of the DigestValue element shall be the base64 encoding of this bit string viewed as an 20-octet octet stream. Example: the DigestValue element for the message digest
A9993E36 4706816A BA3E2571 7850C26C 9CD0D89D
from Appendix A of the SHA-1 standard would be
<DigestValue>qZk+NkcGgWq6PiVxeFDCbJzQ2J0=</DigestValue>
The MD5 algorithm identifier is urn:rsasdi-com:md5. The MD5 algorithm takes no parameters. An example of an MD5 DigestAlg element is
<DigestAlg Algorithm="urn:rsasdi-com:md5"/>
The MD5 digest algorithm produces a sequence of bytes. The content of the DigestValue element shall be the base64 encoding of this sequence. Example: the DigestValue element for the message digest
F96B697D 7CB7938D 525A2F31 AAF161D0
from the test suite of the sample implemention of in RFC 1321 would be
<DigestValue>+WtpfXy3k41SWi8xqvFh0A==</DigestValue>
The HMAC algorithm identifiers are urn:ietf-org:hmac-sha1 and urn:ietf-org:hmac-md5. The HMAC algorithm takes the truncation length in bits as a parameter (parameter identifier urn:ietf-org:hmac-outputlength). An example of an HMAC SignatureAlg element:
; Is this how we wish to do parameters? -MB
<SignatureAlg Algorithm="urn:ietf-org:hmac-sha1">
<Parameter type="urn:ietf-org:hmac-outputlength">
<Integer value="128"/>
</Parameter>
</SignatureAlg>
; This is different than what the Brown draft/IOTP has. I can see some added flexibility to this HMAC approach but I'd rather stick to the RFC 2104 specification. HOWEVER: I am speaking from ignorance; I don't now why it was done that way. -MB
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
<SignatureValue>kpRyejY4uxwT9I74FYv8nQ==</SignatureValue>
The DSA algorithm identifier is urn:nist-gov:dsa. The DSA algorithm takes no parameters. An example of a DSA SignatureAlg element is
<SignatureAlg Algorithm="urn:nist-gov:dsa"/>
The output of the DSA algorithm consists of a pair of integers usually referred by the pair (r, s). The signature value shall consist of the base64 encoding of the concatenation of two octet-streams that respectively result from the octet-encoding of the values r and s. Integer to octet-stream conversion shall be done according to the I2OSP operation defined in the PKCS #1 specification with a k parameter equal to 20. Example: the SignatureValue element for a DSA signature (r, s) with values specified in hexadecimal
r = 8BAC1AB6 6410435C B7181F95 B16AB97C 92B341C0
s = 41E2345F 1F56DF24 58F426D1 55B4BA2D B6DCD8C8
from the example in Appendix 5 of the DSS standard would be
<SignatureValue>i6watmQQQ1y3GB+VsWq5fJKzQcBB4jRfH1bfJFj0JtFVtLotttzYyA==</SignatureValue>
The expression "RSA algorithm" as used in this document refers to the RSASSA-PKCS1-v1_5 algorithm described in RFC 2437.
The RSA algorithm identifiers are urn:rsasdi-com:rsa-sha1 and urn:rsasdi-com:rsa-md5. The RSA algorithm takes no parameters. An example of an RSA SignatureAlg element is
<SignatureAlg Algorithm="urn:rsasdi-com:rsa-sha1"/>
The output of the RSA algorithm is an octet string. The SignatureValue content for an RSA signature shall be the base64 encoding of this octet string. Example: <insert example here>
The algorithm identifier for the null canonicalization is http://www.w3.org/1999/10/signature-core/null. An example of a null canonicalization CanonicalizationAlg element is
<CanonicalizationAlg Algorithm="http://www.w3.org/1999/10/signature-core/null"/>
The null canonicalization produces a message byte-for-byte identical with the original resource. No character set, line ending, or white space normalization is done.
This algorithm is appropriate for applications where the resource to be signed is not XML, or where the XML document will be exactly preserved. For many applications, one of the other canonicalization algorithms will be more appropriate.
The algorithm identifier for the minimal canonicalization is http://www.w3.org/1999/10/signature-core/minimal. An example of a minimal canonicalization CanonicalizationAlg element is
<CanonicalizationAlg Algorithm="http://www.w3.org/1999/10/signature-core/minimal"/>
The minimal canonicalization algorithm:
This algorithm is only applicable to XML resources.
; Bartel & Simon will discuss and propose some other text.
The algorithm identifier for XML canonicalization is http://www.w3.org/1999/07/WD-xml-CanonicalizationAlg-19990729. An example of an XML canonicalization CanonicalizationAlg element is
<CanonicalizationAlg Algorithm="http://www.w3.org/1999/07/WD-xml-CanonicalizationAlg-19990729"/>
See the XML Canonicalization specification.
The algorithm identifier for XML canonicalization is urn:ietf-org:dom-xml-canonicalization. An example of an XML canonicalization CanonicalizationAlg element is
<CanonicalizationAlg Algorithm="urn:ietf-org:dom-xml-canonicalization"/>
Algorithm details to be determined.
To be determined.
; Insert Boyer proposal. -JR
; Specify that they are processed in order and that more than one particular instance of any transformation may be specified.. -JR
These sections describe the operations to be performed as part of signature generation and validation. The description is of a logical behavior and does not specify an order of execution, nor specify discrete steps.
; Solo, do many thing here! <smile> - JR
Transformations determined by application to object being signed. Object reference element(s) including location of object, digest,
and transformation and digest algorithm elements, if required. SignedInfoelement with SignatureAlg, CanonicalizationAlg
(for SignedInfo), and Object reference(s). SignedInfobased on algorithms in
step d. f) construct signature document with SignedInfo, Object
(s) (if desired, encoding may be different than that used for signing), KeyInfo
(if required), and SignatureValue. Transformations (e.g. CanonicalizationAlg) to the signed
object(s) based on all Object reference(s) in the SignedInfoelement.
Object
reference(s). If the object is contained within the Object element, only the
object itself is hashed (i.e. the <Object > and </Object
> tags are excluded). SignedInfo(if mismatch, validation
fails). SignedInfoelement based on the canonicalization algorithm
ID in SignedInfo(or based on the default if absent). KeyInfo or externally. SignatureValue based on the SignatureAlg in the SignedInfoelement,
the key obtained in step c, and the results of step d. - Digest calculation is performed
over the SignedInfoelement including start and end tags. Note that while a signature may validate (a key was properly applied to content to
yield the stated SignatureValue) this does not mean applications will
necessarily trust or accept the signature. For instance, perhaps the assertions within the
content that was signed could not be confirmed or validated themselves.
; place combined DTD back in here at end..
; need to fix this up some more - JR
<Signature
xmlns="http://www.w3.org/1999/10/signature-core">
<SignedInfo Id="5">
<CanonicalizationAlg Algorithm="null"/>
<SignatureAlg algorithm="urn:nist-gov:dsa"/>
<ObjectReference>
<Location HREF="..."/>
<!-- pointer to external signedobject
-->
<Type>text/plain;
charset="us-ascii"</Type>
<Transformations>
<CanonicalizationAlg
Algorithm="http://www.w3.org/1999/10/signature-core/null">
<Encoding
Algorithm="urn:dsig:base64"/>
</Transformations>
<DigestAlg Algorithm="urn:nist-gov:sha1"/>
<DigestValue>a23bcd43"</DigestValue>
</ObjectReference>
<ObjectReference>
<Location HREF="#timestamp"/> <!--
points to Object below -->
<Type
type="http://www.w3.org/1999/10/signature-core/signatureattributes"/>
<Transformations>
<CanonicalizationAlg
Algorithm="http://..."/>
</Transformations>
<DigestAlg Algorithm="urn:nist-gov:sha1"/>
<DigestValue>a53uud43"</DigestValue>
</ObjectReference>
</SignedInfo>
<SignatureValue
encoding="urn:dsig:base64">dd2323dd</SignatureValue>
<Object id="timestamp1"
type="http://www.w3.org/1999/10/signature-core/signatureattributes " >
<timestamp about="#5"
xmlsn="http://www.ietf.org/rfc/1234">
<date>19990908</date>
<time>14:34:34:34</time>
</timestamp>
</Object>
<KeyInfo>
<keyname>Solo</keyname>
</keyinfo>
</Signature>
SignedInfoand for objects. Other
defaults. Mandatory to implement cryptographic algorithms and KeyInfo types. SignedInfoto
the signed object, and what rules need to be defined for the ID attributes in SignedInfoand
Object ? Applications are recommended to ensure signers understand the actual resulting content that is being signed after transformations are applied. Users should not be tricked into signing a native content that is transformed into something that the user would not have signed otherwise. This recommendation applied to transformations specified in the signature block, as well as transformations found within the document itself.
; This list was generated by basically looking at the participants list and including the subset of those that posted something in the last two weeks. If you want to be added, let the Chairs know (see Contributor Policies ). - JR
We define the following types for use in identifying XML resources that include Signture semantics.