I am not saying that crypto agility is necessarily bad, I am saying that a reflexive response that doing things just one way without looking at the arguments is not a very compelling response.
Jim From: Breno de Medeiros [mailto:[email protected]] Sent: Tuesday, September 04, 2012 2:18 PM To: Jim Schaad Cc: Mike Jones; [email protected] Subject: Re: [jose] Use of Base64 encoding Crypto agility is necessary because security of crypto algorithms and key sizes change over time. So supporting multiple crypto algorithms is required for a standard that doesn't want to become obsolete within a few years. It's not a case of flexibility but of necessity. Also, availability of different crypto algorithms varies widely between platforms, so being able to support multiple algorithms is a must to ensure wide adoption -- porting a new crypto algorithm to a platform is a very large effort. OTOH: - Base64URL encoding is quite trivial to add to a platform that doesn't have it - Base64URL encoding is not likely to be deprecated in the foreseeable future On Tue, Sep 4, 2012 at 2:10 PM, Jim Schaad <[email protected]> wrote: I hope that you have a better response than this. If what you say is true then we should eliminate a large number of the cryptographic algorithms that have been proposed as they provide multiple ways of doing things. Do you really believe that the difference in the receiving software is going to be that different based on if base64 or base64URL encoding is used on a binary value? Jim > -----Original Message----- > From: Mike Jones [mailto:[email protected]] > Sent: Tuesday, September 04, 2012 1:46 PM > To: Jim Schaad; [email protected] > Subject: RE: [jose] Use of Base64 encoding > > Having multiple ways to do something never helps improve interop > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of > Jim Schaad > Sent: Tuesday, September 04, 2012 1:38 PM > To: [email protected] > Subject: [jose] Use of Base64 encoding > > <personal> > > I was struck by the questions of which base64 encoder should be used in the > different documents that the working group employed and I started going > through the different locations in the document to see where and how much > it mattered if the base64 or base64URL encoder was used. This message > represents my conclusions and leads to some questions > > 1. The simple dot encoding of the objects does require it as it will possibly be > sent as part of a URL 2. If you are going to be in a space constrained > environment then you MIGHT want it as it will shrink the result, however > doing a solution that deals with binary data more generally would be a better > solution. > 3. Joe might have an argument that only doing things one way is simpler, > however that argument can apply in both directions > > The rest of the time I don't think it matters which of the encoding formats is > used. If you are looking at the SHA-1 hash of a certificate, does it matter if > you use base64 or base64URL, not except for the minor size increase. The > padding characters themselves are protected from the URL by the outside > base64URL encoding. > > Except for the case of the dot encoding step, I think that the use of base64 > URL can be dropped from a MUST to a SHOULD with the justifications being > explained. It was stated at the F2F that the difference in the decoders is > minimal so there is no reason not to allow there and this would allow > different people to make different decisions on this issue. > > Jim > > > _______________________________________________ > jose mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/jose _______________________________________________ jose mailing list [email protected] https://www.ietf.org/mailman/listinfo/jose -- --Breno
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