XML Signature Core Syntax

David Solo dsolo@alum.mit.edu
draft-ietf-xmldsig-core-01.txt
22 October 1999

Top level structure

<Signature>
 <SignedInfo>
 <SignatureValue> 
 <KeyInfo>?
 <Object>*
</Signature>

• KeyInfo is not signed, but may be bound
• Some objects defined

SignedInfo

<SignedInfo>
 <CanonicalizationMethod>?
 <SignatureMethod> 
 <ObjectReference ID= Location= Type=? >
 <Transforms>?
 <DigestMethod>
 <DigestValue>
 </ObjectReference>+
</SignedInfo>

• No default for c14nMethod, null if absent

Location Issues

• Should it be signed
• Form - URI or Idref
• Location ="" denotes this document
• Location absent assumes application knows
• only allowed if a single ObjectReference is present

Method syntax

• Still discussion on structure for parameters

Transforms

<Transforms>
<Transform>+
</Transforms>

 <Transform Algorithm= Encoding= Type= Charset= >
 ANY
</Transform>

• Applied in order to associated object prior to digest
• No defaults, only perform what is explicit
• encode/decode, c14n, Xpath, XSLT, ….

Object

<Object ID= Type= Encoding=>
ANY
</Object>

• Can carry any type of data
• Specific definitions for
• Manifest
• Package
• SignatureProperties

Algorithms

• Required
  • SHA1
  • Base64
  • HMAC-SHA1
  • DSAwithSHA1
  • Minimal c14n
• Recommended
  • RSAwithSHA1
  • XML c14n
  • XSLT, Xpath, Xpointer
• Optional
  • ECDSA