End-to-middle Security in SIP draft-ietf-sip-e2m-sec-00.txt

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End-to-middle Security in SIPdraft-ietf-sip-e2m-s
ec-00.txt

• Kumiko Ono
• NTT Corporation

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Open Issues

• 1 UAC is expected to differently react with a
  493 (Undecipherable) error, depending on its
  sender.
• The error response doesn't include who the sender
  is.
• Options
• A new error code for proxy, 496 Proxy
  Undecipherable
• The same error code, use the URI in the PKC
  appended to the response.
• 2 How does a proxy request to disclose a
  specific Content-Type or the whole body?
• In the current version, a proxy server responds
  with an error code and Warning header indicating
  which Content-Type is to be disclosed.
• i.e., Warning 380 proxy.com "Required to view '
  application/sdp
• There is no way to request the disclosure of
  whole body.
• Proposal
• An error code without Warning header has the
  semantics of proxys requesting the disclosure of
  the whole body.

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Open Issues (contd.)

• 3 Do we need the labeling mechanism to instruct
  a proxy server to validate the signature?
• A minor usecase.
• Options
• 1. Leave it,
• 2. Drop it.
• 4 How does a UA know if the target proxy server
  complied to the UAs request?
• Options
• Proxy adds a flag in the response.
• Proxy rejects when it cant comply to the UAs
  request.
• 3. No need.

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Next Steps

• Any other open issues?
• Can we get some experts review?