Thanks. I will push it to the next rev.

2014-05-15 8:43 GMT+09:00 Josh Mandel <[email protected]>:

> Forgive me if this is well-trodden territory, but I would have expected
> the security considerations in this proposal to include a note to the
> effect of:
>
> "In a scenario where a mobile client is contending with malicious apps on
> the same device that listen on the same custom URL scheme, it's important
> to keep in mind that a malicious app can initiate its own authorization
> request. Such a request  would appear the same as a legitimate request from
> the end-user's perspective. So in this case, a malicious app could request
> its own verifier code and successfully obtain authorization using the tcse
> protocol."
>
> Obviously this does not negate the value of the proposal, but it's
> something I'd expect readers to keep in mind.
>
> In particular, it has very strong implications for whitelisted
> authorizations, where no end user interaction is required. In such a case,
> a malicious app could initiate a request at any time and the user would not
> be in the loop to raise a question about its legitimacy.
>
> On May 9, 2014 4:51 PM, "Brian Campbell" <[email protected]>
> wrote:
> >
> > I notice that code_verifier is defined as "high entropy cryptographic
> random string of length less than 128 bytes"  [1], which brought a few
> questions and comments to mind. So here goes:
> >
> > Talking about the length of a string in terms of bytes is always
> potentially confusing. Maybe characters would be an easier unit for people
> like me to wrap their little brains around?
> >
> > Why are we putting a length restriction on the code_verifier anyway? It
> seems like it'd be more appropriate to restrict the length of the
> code_challenge because that's the thing the AS will have to maintain
> somehow (store in a DB or memory or encrypt into the code). Am I missing
> something here?
> >
> > Let me also say that I hadn't looked at this document since its early
> days in draft -00 or -01 last summer but I like the changes and how it's
> been kept pretty simple for the common use-case while still allowing for
> crypto agility/extension. Nice work!
> >
> > [1] http://tools.ietf.org/html/draft-sakimura-oauth-tcse-03#section-3.3
> >
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> >
>
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-- 
Nat Sakimura (=nat)
Chairman, OpenID Foundation
http://nat.sakimura.org/
@_nat_en
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