If the receiver doesn't recognize the new alg parameter it must throw an error.
I can't imagine processing and returning success with an unknown parameter value. On 2013-08-19, at 5:06 PM, "Jim Schaad" <[email protected]> wrote: > What happens when I give you a new alg parameter value because I have defined > a new algorithm? > > From: [email protected] [mailto:[email protected]] On Behalf Of Mike > Jones > Sent: Monday, August 19, 2013 1:31 PM > To: Phil Hunt > Cc: Richard Barnes; jose issue tracker; [email protected]; John Bradley; Justin > Richer; [email protected] > Subject: Re: [jose] #36: Algorithm "none" should be removed > > Because it breaks the invariant that you use the “alg” parameter value to > determine how to process the JOSE object. > > From: Phil Hunt [mailto:[email protected]] > Sent: Monday, August 19, 2013 1:29 PM > To: Mike Jones > Cc: Richard Barnes; John Bradley; jose issue tracker; Justin Richer; > [email protected]; [email protected] > Subject: Re: [jose] #36: Algorithm "none" should be removed > > I think it is dangerous to say signature is valid if alg:none. Richard is > right. The app will get a binary response and will assume there was a > signature. > > Why not simply detect if "alg":"somealg" is present and if not, proceed > direct to payload processing? > > Phil > > @independentid > www.independentid.com > [email protected] > > > > > > > > On 2013-08-19, at 1:23 PM, Mike Jones <[email protected]> wrote: > > > It is accepted. That doesn’t mean that the application should accept it > unless it validates that the actual algorithm used meets its security > requirements, whether it’s “none”, or not. (For instance, if you require > HS512 or ES512, your application will need to reject inputs that used HS256, > etc.) This is a basic requirement for secure applications – not a new > requirement created by the presence of “none”. > > -- Mike > > From: Richard Barnes [mailto:[email protected]] > Sent: Monday, August 19, 2013 1:21 PM > To: Mike Jones > Cc: John Bradley; Justin Richer; jose issue tracker; [email protected]; > [email protected] > Subject: Re: [jose] #36: Algorithm "none" should be removed > > But that signature is valid for that algorithm. So a generic JWS parser will > show it as accepted. > > > On Mon, Aug 19, 2013 at 4:18 PM, Mike Jones <[email protected]> > wrote: > Having an empty signature segment already makes it recognizably different. > > From: Richard Barnes [mailto:[email protected]] > Sent: Monday, August 19, 2013 1:18 PM > To: John Bradley > Cc: Justin Richer; jose issue tracker; Mike Jones; [email protected]; > [email protected] > Subject: Re: [jose] #36: Algorithm "none" should be removed > > On Mon, Aug 19, 2013 at 3:48 PM, John Bradley <[email protected]> wrote: > In OAuth and Connect there are cases where you are receiving tokens from > multiple sources. By allowing none as a alg option we can process signed or > unsigned tokens with the same basic handler by inspecting the first segment. > I note currently that while none has three segments the last segment must be > empty. I think that is sufficient to keep people from becoming confused. > > Making it two segments will break existing parsers for no good reason. > > No, there's a very good reason. Something that is not signed should not be > accepted as a JSON Web Signature object. Acceptance of a JWS implies that > the payload and protected headers were integrity protected from the signer; > that is not true for "alg":"none". > > Also, it's not clear that this change will break existing parsers. For > example, the NimbusDS parser would successfully parse a two-segment object as > a "plain JWT" > <https://bitbucket.org/nimbusds/nimbus-jose-jwt/src/ca58ff0ece35243aa6546583dffcd236dcea26d2/src/main/java/com/nimbusds/jwt/JWTParser.java?at=master> > > > What we call it I am flexible about, if it is a unsigned JOSE object in > compact serialization i am fine. > > I would also be completely fine with an unsigned "header + content" structure > (though I don't think it adds any value). But it must be recognizably > different from JWS. > > --Richard, who is honestly kind of floored that there's all this argument > over a single "." character > > > > > > John B. > > On 2013-08-19, at 12:30 PM, Justin Richer <[email protected]> wrote: > > > I don't normally jump into the discussion on this list, but I've been using > > the output of JOSE for quite some time now and am a committer on the > > NimbusDS JOSE JWT library. However, with tonight's call coming up (which I > > won't be able to make) I wanted to jump in and say that from my > > perspective, alg:none makes a lot of sense. There's a need for being able > > to send unsigned content with JOSE objects, and that's been pretty well > > established by others on the list here. As an implementor, though, I think > > it makes the most sense to have the unsigned content be parallel in > > structure to the signed content. When reading a string and constructing > > objects, our library parses the header and dispatches the parser based on > > the "alg" parameter. > > > > And as Mike points out, alg:none has been in the spec as required to > > implement for ages now, and it hasn't caused the horrible security holes > > that people are predicting. > > > > -- Justin > > > > On 08/01/2013 07:23 AM, jose issue tracker wrote: > >> #36: Algorithm "none" should be removed > >> > >> > >> Comment (by [email protected]): > >> > >> And sure enough, working groups across the IETF are having to explicitly > >> forbid the use of null ciphersuites. They provide empirical evidence that > >> this design pattern is a bad idea. > >> > >> As I've pointed out before, you can add that verification algorithm, but > >> you will not have a good time writing security considerations around it. > >> Checking that you support "none" is not enough -- you have to check that > >> *nothing* *else* in the header could possibly indicate that a different > >> signature algorithm should be used. > >> > >> So we have something that (1) causes a lot of spec work, (2) causes > >> security vulnerabilities under likely implementaiton designs, and (3) has > >> no use case, and (4) will haunt us for years to come (how many times do > >> you want to write 'MUST NOT use "alg":"none"'?). Sounds like a recipe for > >> success! > >> > > > > _______________________________________________ > > jose mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/jose > > > > _______________________________________________ > jose mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/jose
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