#2 seems like a reasonable path forward.

On Wed, Sep 18, 2013 at 5:04 PM, Mike Jones <[email protected]>wrote:

>  We discussed issue #50 on Monday’s call and it seems like there are two
> viable choices before us:****
>
> ** **
>
> 1.  Continue to have “cty” values come from a JOSE registry, while
> allowing MIME Media Type values to also be used, if desired.****
>
>   ADVANTAGES:****
>
>     + Keeps values compact****
>
>     + Uses case-sensitive value comparison (like all other JOSE
> parameters), avoiding internationalization issues****
>
>     + Already working in production deployments****
>
>   DISADVANTAGES:****
>
>     - Creates a content type value space distinct from the widely used
> IANA Media Type Registry (http://www.iana.org/assignments/media-types).***
> *
>
>     - Requires a convention to consistently spell media type names so they
> can be matched case sensitively, when used.****
>
>     - Names can come from one of two registries, rather than just one
> (possibly being disambiguated by the presence of a “/” in the name).****
>
> ** **
>
> 2.  Accept a form of James’ proposal described in
> http://trac.tools.ietf.org/wg/jose/trac/ticket/50, in which “cty” values
> are defined to hold MIME Media Type values, also specifying that the
> “application/” prefix may be omitted for compactness purposes.  (MIME Media
> Type values are not case sensitive and are limited to ASCII.)  Furthermore,
> we could keep this from being a breaking change for JWTs by RECOMMENDING
> that the value “cty”:”JWT” continue to be used for nested JWTs (rather than
> “application/jwt” or “jwt”, which would break existing deployments).****
>
>   ADVANTAGES:****
>
>     + Retains the ability to have compact values for application/* media
> types****
>
>     + Uses only the widely used IANA Media Type Registry****
>
>     + Can be deployed without breaking changes, provided people use the
> existing spellings “JWT”, “JWK”, and “JWK-SET” when creating content for
> those media types****
>
>   DISADVANTAGES:****
>
>     - Uses case-insensitive value comparison, which can lead to
> interoperability problems****
>
>     - Implementations have to be aware of the need to prefix values not
> containing a “/” with “application/” to get normal media type names****
>
> ** **
>
> New text for “cty” under option 2 would look something like this:****
>
> ** **
>
> *4.1.9.  "cty" (Content Type) Header Parameter*
>
> The cty (content type) header parameter is used to declare the MIME Media
> Type [IANA.MediaTypes] of the secured content (the payload) in contexts
> where this is useful to the application. This parameter has no effect upon
> the JWS processing. Use of this header parameter is OPTIONAL.****
>
> Per [RFC 2045], all media type values, subtype values, and parameter names
> are case-insensitive.  However, parameter values are case-sensitive unless
> otherwise specified for the specific parameter.****
>
> To keep messages compact in common situations, a sender MAY omit an
> "application/" prefix of a media type from a "cty" value when no other '/'
> appears in the media type. A recipient reconstructing the media type MUST
> prepend "application/" to a "cty" value that does not contain a '/'.****
>
> ** **
>
> As background, see
> http://tools.ietf.org/html/draft-ietf-jose-json-web-signature-16#section-4.1.9for
>  the current “cty” text, see
> http://tools.ietf.org/html/draft-ietf-jose-json-web-signature-16#section-4.1.8for
>  the related “typ” text, and see
> http://tools.ietf.org/html/draft-ietf-jose-json-web-signature-16#section-8.2for
>  the Type Values Registry.
> ****
>
> ** **
>
> I’m curious what people’s preferences are between the two choices.  I can
> personally live with either outcome, since both can be deployed without
> breaking existing deployments.  At this point, it seems to come down to a
> question of personal taste.  Your thoughts…?****
>
> ** **
>
>                                                                 -- Mike***
> *
>
> ** **
>
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>
>
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