[jose] Richard Barnes' Discuss on draft-ietf-jose-json-web-encryption-33: (with DISCUSS and COMMENT)

["Richard Barnes" <[e-mail]>]

Richard Barnes has entered the following ballot position for
draft-ietf-jose-json-web-encryption-33: Discuss

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DISCUSS:
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Overall, this document is in much more solid shape than when it began. 
Thanks to the WG for a lot of hard work.  I only have one remaining
concern, that should hopefully be easy to address.

Section 7.2.
I've had several implementors trying to use JWE in the JSON serialization
ask why it was necessary to include a "recipients" array in cases where
there's only one recipient.  It seems like this is going to be a major
barrier to deployment and re-use, so I would propose including the
following text:
"""
In cases where the JWE is encrypted for only one recipient, the
"recipients" array will contain a single object.  In such cases, the
elements of the "recipients" array MAY be included at the top level of
the JWE object.  If the generator of a JWE chooses to use this
representation then all unprotected header parameters MUST be carried in
the "header" field, and the "unprotected" field MUST be absent.  A
JSON-formatted JWE that contains a "recipients" field MUST NOT contain a
"header" or "encrypted_key" field, and vice versa. 
"""
This may also require some other changes where "recipients" is relied on,
e.g., in Section 9.


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COMMENT:
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Section 3.3.
Why doesn't this example include the JSON encoding?

Section 4.1.3.
"This Header Parameter MUST be integrity protected"
Why is this the case?  There is no security reason that "zip" must be
integrity-protected, and this requirement isn't made for any other
parameter.

Section 7.2.
The requirement that the "recipients" field MUST be present seems odd. 
What's the justification for this?

Appendix A seems kind of unnecessary given draft-ietf-jose-cookbook.