From the AS side you probably want to know what the max size you need to store per code.
On the call to the token endpoint it is a POST so size should not be an issue. On May 16, 2014, at 3:10 PM, Nat Sakimura <[email protected]> wrote: > Now that I cannot remember what limit we were hitting, it might be a good > idea to remove the constraint and see if anyone protests. > > What do you think? > > Nat > > > 2014-05-14 20:46 GMT+09:00 Brian Campbell <[email protected]>: > That too would suggest that the length limit be on code_challenge because > that's the parameter that will be on URIs getting passed around. The > code_verifier is sent directly in the POST body from client to AS. > > > On Tue, May 13, 2014 at 12:52 AM, Nat Sakimura <[email protected]> wrote: > +1 for octet. We used to have "bytes" in JW* so I used "bytes" here, while at > the same time complaining in Jose that it should be "octet". JW* changed to > "octet" but I failed to sync with it in the last few edits. > > I do not quite remember which platform, but the reason for the limit was that > some platform had some limitations as to the length of the sting to be passed > to it through URI and we did not want the challenges to be truncated by that > limit. > > Best, > > Nat > > > 2014-05-13 6:56 GMT+09:00 Brian Campbell <[email protected]>: > > And it'd give the AS some direct guidance on protecting itself from crazy > long code_challenge values rather than relying on the client not to do > something creative. > > > On Mon, May 12, 2014 at 3:54 PM, Brian Campbell <[email protected]> > wrote: > Right but that's why I'm asking why not just put the limit on code_challange > rather than inferring it from code_verifyer + challenge algorithm, which > probably bounds it but doesn't necessarily do so? It's not a big deal but > would read more clearly, I think. > > > On Mon, May 12, 2014 at 3:48 PM, John Bradley <[email protected]> wrote: > I think octets is more consistent with other JW* and OAuth specs. > > The code_challange is the same length as the code_verifyer or is a hash of > the code_verifyer so likely smaller than 128octets (43 ish for base64 256 bit) > > Limiting the code_verifyer size sets the upper bound for code_challange, > unless someone comes up with a really creative code challenge algorithm. > > I will talk to nat about changing it to octets when I see him tomorrow. > > John B. > > On May 12, 2014, at 11:15 PM, Derek Atkins <[email protected]> wrote: > > > Brian Campbell <[email protected]> writes: > > > >> 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? > > > > It depends if it really is characters or bytes. For example there are > > many multi-byte UTF-8 characters, so if it really is bytes then saying > > characters is wrong because it could overflow. So let's make sure we > > know what we're talking about. Historically, if we're talking bytes the > > IETF often uses the phrase "octets". Would that be less confusing? > > > >> 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 > > > > -derek > > > >> _______________________________________________ > >> OAuth mailing list > >> [email protected] > >> https://www.ietf.org/mailman/listinfo/oauth > > > > -- > > Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory > > Member, MIT Student Information Processing Board (SIPB) > > URL: http://web.mit.edu/warlord/ PP-ASEL-IA N1NWH > > [email protected] PGP key available > > > > > -- > > Brian Campbell > Portfolio Architect > @ [email protected] > +1 720.317.2061 > Connect with us… > > > > > > -- > > Brian Campbell > Portfolio Architect > @ [email protected] > +1 720.317.2061 > Connect with us… > > > > _______________________________________________ > OAuth mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/oauth > > > > > -- > Nat Sakimura (=nat) > Chairman, OpenID Foundation > http://nat.sakimura.org/ > @_nat_en > > > > -- > > Brian Campbell > Portfolio Architect > @ [email protected] > +1 720.317.2061 > Connect with us… > > > > > > -- > Nat Sakimura (=nat) > Chairman, OpenID Foundation > http://nat.sakimura.org/ > @_nat_en
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