XKMS

1
XKMS

• Dr. Phillip Hallam-BakerVeriSign Inc.

2
Revision of XKMS

• Principles
• Syntax Issues
• Split Register Function
• Trust Model Selection
• Securing XKMS Messages
• Error Handling

3
Principles

• Version 1.2 or 2.0 ?
• See syntax, split Register
• Priority is simple client
• Transfer irreducible complexity to server
• Optional Features
• Client can never be required to ask questions
• Server can be required to answer them
• Answer might be I dont do that

4
Syntax

• Take advantage of XML Schema rec.
• Align to XML Signature, SAML conventions
• Every element is of named type
• No global attributes
• Allow services to advertise features through WSDL
• Allow reuse of elements/types in X-Bulk

5
Split Register Function

• Most requested change
• Separate Register Functions
• Register
• Should server/user generation be separate as
  well?
• Revoke
• Reissue
• Recover
• 2.0 beta 1 Does not change Authentication
• Server/User Authentication model is bogus
• Rename some elements to make more descriptive
• Respond ? RespondWith etc.

6
Trust Model Selection

• Options
• Client describes trust model
• Incompatible with XKMS philosophy
• Would require very close binding to underlying
  PKI
• Client refers to trust model by URL
• Client accesses different trust models via
  different service URLs
• In either case need to bind answer to trust model

7
Securing XKMS Messages

• Options
• SSL
• OK, but requires an X.509 parser
• Transport level is limited
• WS-Security
• Not yet proposed as WG
• Might be something to address after XKMS 2.0
• The bootstrap problem
• Pre-profile WS-Security

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Pre-profile WS-Security

• Sign Encrypt
• XML-Signature, XML-Encryption
• Encapsulation
• Wrap?
• Define own SOAP headers?
• Definitely want detachability.
• Need to bind in
• Web Service Port
• Digest of request if not authenticated

9
Robustness

• Deadlock Livelock
• The need for a maximum forwarding counter
• Without control chained requests will deadlock or
  livelock.
• Chained requests important for e.g. Identrus.

10
Error Handling

• Specify fault behavior in greater detail
• Use implementation experience

11
Pending Response

• Fix this!
• We need the facility