W3C home > Mailing lists > Public > public-credentials@w3.org > November 2018

Re: JSON-LD vs JWT for VC

From: Mike Lodder <mike@sovrin.org>
Date: Fri, 2 Nov 2018 10:10:54 -0600
Message-ID: <CAPhnkk4-qm-zbWgKgVNPCZssE6bogQtRb+MaFJyabcBgzyi-1w@mail.gmail.com>
To: anders.rundgren.net@gmail.com
Cc: Chris Boscolo <chris@boscolo.net>, "W3C Credentials CG (Public List)" <public-credentials@w3.org>
The point that Chris is making I agree with. If you can alter the data
after a signature has been computed in anyway this is considered a big NO
NO by many security personnel.

On Fri, Nov 2, 2018 at 10:01 AM Anders Rundgren <
anders.rundgren.net@gmail.com> wrote:

> On 2018-11-02 16:02, Chris Boscolo wrote:
> >
> >
> > On Thu, Nov 1, 2018 at 11:51 PM Anders Rundgren <
> anders.rundgren.net@gmail.com <mailto:anders.rundgren.net@gmail.com>>
> wrote:
> >  >     It is bit in the same veins as the claim that an intermediary
> setting the JWS signature algorithm to "none" opens a security hole [1].
> It does not, a receiver MUST always define a policy and if the input
> doesn't meet that policy, the message is rejected.  Leaving an
> application's policy to a general purpose library is based on a
> misconception.
> >
> >
> > Exactly!  This problem resulted from the fact that the parameters
> describing the way the data should be protected are not part of the
> signature/hmac.  A couple decades of building security software have taught
> us some best practices, why would deviate from them with new proposals?
>
> You mean JWS and LD-signatures do not protect such data?
>
> I believe this is incorrect, at least for JWS.  That the "none" algorithm
> doesn't secure anything is for sure but the use-case for "none" is simply
> keeping unsigned messages in the same (ugly) format as signed ditto.
>
> Enveloped signatures (
> https://tools.ietf.org/html/draft-erdtman-jose-cleartext-jws-01) do no
> suffer from this problem, although some people claim that you can just
> remove the signature element to fool the receiver into accepting something
> it should not.  That's what application policies deal with.
>
> Anders
>
>
>
>

-- 
Mike Lodder
Security Maven
Received on Friday, 2 November 2018 16:11:54 UTC

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