The only question is if the OAuth ext review list is the correct place for review.
I don't have a problem with re using an existing review process for a new registry, if that works for people. John B. > On Dec 3, 2014, at 9:09 AM, Hannes Tschofenig <hannes.tschofe...@gmx.net> > wrote: > > I just looked at the IANA consideration section and I noticed that there > is no policy defined for adding, or deprecating values from various > registries, such as the code_challenge_method. > > So, you can essentially decide about how easy or difficult you can make > it for yourself. > > I would think that 'Specification Required' would be appropriate. > You can copy the relevant text from > https://tools.ietf.org/html/rfc6749#section-11 and adjust it accordingly. > > Ciao > Hannes > > On 12/03/2014 01:01 PM, John Bradley wrote: >> We have been thinking that new hash functions and new mechanisms (eg >> ECDH-ES) would be treated the same and require a spec and review. >> >> (At some point I will do a asymmetric extension so that the key can also be >> used to encrypt POP keys back to the client, but I don't want to make this >> spec look to complicated) >> >> Any mechanism using a challenge & verifier approach could fit in to the >> defined parameters, a different hash like SHA3 is simple in that it just be >> a replacement of the hash function. >> >> I think guidance id fine as long as it doesn't limit future options. >> >> John B. >> >> >>> On Dec 3, 2014, at 8:46 AM, Hannes Tschofenig <hannes.tschofe...@gmx.net> >>> wrote: >>> >>> Hi John, >>> >>> I believe it makes sense to give recommendations for extensions (if you >>> envision them). Of course, I hope that we do not see a flood of >>> extensions that all use different hash functions. >>> >>> Changing the mechanism to something that provides even stronger security >>> properties would definitely require a new specification and review. >>> >>> Ciao >>> Hannes >>> >>> >>> On 12/03/2014 12:37 PM, John Bradley wrote: >>>> Thanks Hannes. >>>> >>>> Other methods such as different hashes need to be added via extension >>>> specs. >>>> >>>> Are you saying that we should set minimum recommendations for them. >>>> >>>> It is also possible that those methods might use something other than >>>> hashing. Key agreement might be a possibility. >>>> >>>> Those properties would all be requirements for selecting a different hash >>>> function. We could add that as a requirement for extensions if you think >>>> that is appropriate. >>>> >>>> John B. >>>> >>>>> On Dec 3, 2014, at 8:17 AM, Hannes Tschofenig <hannes.tschofe...@gmx.net> >>>>> wrote: >>>>> >>>>> Hi all, >>>>> >>>>> I am trying to figure out how to progress the SPOP document and >>>>> therefore I read through the discussion about the code challenge, see >>>>> >>>>> I wanted to share my view about this topic. >>>>> >>>>> As a summary, the mechanism works as follows: >>>>> >>>>> C: Compute code_verifier:=rand() >>>>> C: Compute code_challenge:=func(code_verifier) >>>>> >>>>> (For this discussion, the function func() is SHA-256.) >>>>> >>>>> C: Send(Authz Request + code_challenge,S) >>>>> >>>>> S: store code_challenge >>>>> S: Send(Authz Grant,C) >>>>> >>>>> C: Send(Access Token Request || code_verifier, S) >>>>> >>>>> S: Compute code_challenge':=func(code_verifier) >>>>> S: IF (code_challenge'==code_challenge) THEN SUCCESS ELSE FAIL. >>>>> >>>>> The document currently does not say how much entropy the random number >>>>> has to have. >>>>> >>>>> The text only talks about the output size and SHA-256 indeed produces a >>>>> 256 bit output. >>>>> >>>>> Here is the relevant text: >>>>> >>>>> " >>>>> NOTE: code verifier SHOULD have enough entropy to make it impractical >>>>> to guess the value. It is RECOMMENDED that the output of a suitable >>>>> random number generator be used to create a 32-octet sequence. >>>>> " >>>>> >>>>> I suggest to recommend at least 128 bits, which is inline with the >>>>> recommendations for symmetric ciphers in >>>>> http://tools.ietf.org/html/draft-ietf-uta-tls-bcp-07 >>>>> >>>>> I would also suggest to reference RFC 4086 concerning the creation of >>>>> random numbers. >>>>> >>>>> Furthermore, since you allow other hash functions to be used as well it >>>>> would be good to give guidance about what the properties of those hash >>>>> functions should be. You definitely want a cryptographic hash function >>>>> that provides pre-image resistance, second pre-image resistance, and >>>>> collision resistance. >>>>> >>>>> Given the size of the input and output it is impractical to compute a >>>>> table that maps code_verifies to code_challenges. >>>>> >>>>> This mechanism provides better properties than the "plain" mechanism >>>>> since it deals with an attacker that can see responses as well as >>>>> requests (but cannot modify them). It does not provide any protection >>>>> against a true man-in-the-middle attacker. >>>>> >>>>> Ciao >>>>> Hannes >>>>> >>>>> >>>>> _______________________________________________ >>>>> OAuth mailing list >>>>> OAuth@ietf.org >>>>> https://www.ietf.org/mailman/listinfo/oauth >>>> >>> >> >
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