Re: [OAUTH-WG] Question lengths in draft-sakimura-oauth-tcse-03

[Nat Sakimura <[e-mail]>]

Good! I achieve the purpose :-)

So what would be the appropriate length?
The current one would do?


2014-05-20 22:56 GMT+09:00 Anil Saldhana <[e-mail]>:

>  Brian - I agree with you.  It should be MUST as long as the hard limit
> is generous for usage.
>
>
>
>
> On 05/20/2014 07:09 AM, Brian Campbell wrote:
>
> I'd say it should be a MUST so that implementations are consistent about
> it.
>
>
> On Fri, May 16, 2014 at 3:27 PM, Bill Mills <[e-mail]>wrote:
>
>>  The HTTP specs don't limit these things, but implementations do, and
>> the problems when you run into them are a rea pain.
>>
>>  DO we want to make this a hard limit, or should it be guidance in the
>> form of RECOMMENDED or SHOULD?
>>
>>     On Friday, May 16, 2014 9:35 AM, Brian Campbell <
>> [e-mail]> wrote:
>>    Yeah, I agree with John here. There are a few good reasons to
>> restrict the length of the code_challenge. One is trying to keep the
>> authorization request URI to reasonable size as it will eventually run into
>> various limits on clients and/or servers. The other is constraining the
>> amount of data that an AS needs to store per code.
>>
>>
>>
>>
>> On Fri, May 16, 2014 at 7:41 AM, John Bradley <[e-mail]> wrote:
>>
>> 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 <[e-mail]> 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 <[e-mail]>:
>>
>> 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 <[e-mail]>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 <[e-mail]>:
>>
>>  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 <
>> [e-mail]> 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 <[e-mail]> 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 <[e-mail]> wrote:
>>
>> > Brian Campbell <[e-mail]> 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
>> >> [e-mail]
>> >> 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
>> >       [e-mail]                        PGP key available
>>
>>
>>
>>
>>  --
>>    [image: Ping Identity logo] <https://www.pingidentity.com/>
>> Brian Campbell
>> Portfolio Architect
>>   @ [e-mail]  [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
>>   @ [e-mail]  [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
>> [e-mail]
>> 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
>>   @ [e-mail]  [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/>
>>
>>
>>
>>
>>  --
>> Nat Sakimura (=nat)
>> Chairman, OpenID Foundation
>> http://nat.sakimura.org/
>> @_nat_en
>>
>>
>>
>>
>> _______________________________________________
>> OAuth mailing list
>> [e-mail]
>> https://www.ietf.org/mailman/listinfo/oauth
>>
>>
>>
>
>
> _______________________________________________
> OAuth mailing [e-mail]://www.ietf.org/mailman/listinfo/oauth
>
>
>
> _______________________________________________
> OAuth mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/oauth
>
>


-- 
Nat Sakimura (=nat)
Chairman, OpenID Foundation
http://nat.sakimura.org/
@_nat_en