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/>
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