Issue #26 http://trac.tools.ietf.org/wg/oauth/trac/ticket/26 asks whether the 
semantics of scope strings should be changed to require that the % character be 
interpreted as introducing a percent-encoded character that follows.  My 
proposed resolution is that %-encoding not be required in the specification; 
therefore no textual change would be made to the specification in response to 
this issue.  The reasoning behind this resolution is as follows:

1.  Interpretation of scope strings already requires semantic agreement on the 
meaning of the scope strings between the parties participating the OAuth flow.  
Should an encoding be used for scope strings in a particularly deployment 
context, it is reasonable for participants to have agreed upon that encoding, 
just as they agree on other OAuth configuration parameters.

2.  More than one encoding methodology could reasonably be employed in scope 
strings.  For instance, base64url encoding of scope values could be used in 
some contexts.  Quoting characters with '\' is another possibility.  I see no 
compelling reason to mandate %-encoding over other potential encoding methods.

3.  Mandating %-encoding unnecessarily complicates implementations without 
providing a clear compensating benefit sufficient warrant the additional 
complexity.  For example, it seems unnecessary to mandate that the scope 
strings "email" and "%65mail" MUST compare as being equal in all 
implementations.

4.  If an encoding methodology for scope strings is mandated, this should be 
done in the OAuth Core specification - not the OAuth Bearer Token specification.

5.  I am aware of no existing practice that utilizes %-encoding of scope values.

                                                                -- Mike

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