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 <sakim...@gmail.com> 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 <bcampb...@pingidentity.com>: > > 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 < >> bcampb...@pingidentity.com> 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 <ve7...@ve7jtb.com> 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 <warl...@mit.edu> wrote: >>>> >>>> > Brian Campbell <bcampb...@pingidentity.com> 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 >>>> >> OAuth@ietf.org >>>> >> 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 >>>> > warl...@mit.edu PGP key available >>>> >>>> >>> >>> >>> -- >>> [image: Ping Identity logo] <https://www.pingidentity.com/> >>> Brian Campbell >>> Portfolio Architect >>> @ bcampb...@pingidentity.com [image: phone] +1 720.317.2061 Connect >>> with us… [image: twitter logo] <https://twitter.com/pingidentity> [image: >>> youtube logo] <https://www.youtube.com/user/PingIdentityTV> [image: >>> LinkedIn logo] <https://www.linkedin.com/company/21870> [image: >>> Facebook logo] <https://www.facebook.com/pingidentitypage> [image: >>> Google+ logo] <https://plus.google.com/u/0/114266977739397708540> [image: >>> slideshare logo] <http://www.slideshare.net/PingIdentity> [image: >>> flipboard logo] <http://flip.it/vjBF7> [image: rss feed >>> icon]<https://www.pingidentity.com/blogs/> >>> [image: Register for Cloud Identity Summit 2014 | Modern Identity >>> Revolution | 19–23 July, 2014 | Monterey, >>> CA]<https://www.cloudidentitysummit.com/> >>> >>> >> >> >> -- >> [image: Ping Identity logo] <https://www.pingidentity.com/> >> Brian Campbell >> Portfolio Architect >> @ bcampb...@pingidentity.com [image: phone] +1 720.317.2061 Connect >> with us… [image: twitter logo] <https://twitter.com/pingidentity> [image: >> youtube logo] <https://www.youtube.com/user/PingIdentityTV> [image: >> LinkedIn logo] <https://www.linkedin.com/company/21870> [image: Facebook >> logo] <https://www.facebook.com/pingidentitypage> [image: Google+ >> logo]<https://plus.google.com/u/0/114266977739397708540> [image: >> slideshare logo] <http://www.slideshare.net/PingIdentity> [image: >> flipboard logo] <http://flip.it/vjBF7> [image: rss feed >> icon]<https://www.pingidentity.com/blogs/> >> [image: Register for Cloud Identity Summit 2014 | Modern Identity >> Revolution | 19–23 July, 2014 | Monterey, >> CA]<https://www.cloudidentitysummit.com/> >> >> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org >> https://www.ietf.org/mailman/listinfo/oauth >> >> > > > -- > Nat Sakimura (=nat) > Chairman, OpenID Foundation > http://nat.sakimura.org/ > @_nat_en > -- [image: Ping Identity logo] <https://www.pingidentity.com/> Brian Campbell Portfolio Architect @ bcampb...@pingidentity.com [image: phone] +1 720.317.2061 Connect with us… [image: twitter logo] <https://twitter.com/pingidentity> [image: youtube logo] <https://www.youtube.com/user/PingIdentityTV> [image: LinkedIn logo] <https://www.linkedin.com/company/21870> [image: Facebook logo] <https://www.facebook.com/pingidentitypage> [image: Google+ logo]<https://plus.google.com/u/0/114266977739397708540> [image: slideshare logo] <http://www.slideshare.net/PingIdentity> [image: flipboard logo] <http://flip.it/vjBF7> [image: rss feed icon]<https://www.pingidentity.com/blogs/> [image: Register for Cloud Identity Summit 2014 | Modern Identity Revolution | 19–23 July, 2014 | Monterey, CA]<https://www.cloudidentitysummit.com/>
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