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Re: [jose] Signature algorithm "none"

John Bradley <ve7jtb@ve7jtb.com> Wed, 31 July 2013 15:24 UTC

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From: John Bradley <ve7jtb@ve7jtb.com>
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Date: Wed, 31 Jul 2013 17:24:12 +0200
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References: <CAL02cgQUmNqq62S553muLz3L8Xk9tT1W_jR7j3fHXEhH4wvoVA@mail.gmail.com> <4E1F6AAD24975D4BA5B16804296739436B734340@TK5EX14MBXC284.redmond.corp.microsoft.com> <CAL02cgQhmU2O7=nVJS41iQWHp+EOaY-q8w5TFLtT4=fUrS3jYw@mail.gmail.com>
To: Richard Barnes <rlb@ipv.sx>
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Cc: Mike Jones <Michael.Jones@microsoft.com>, "jose@ietf.org" <jose@ietf.org>
Subject: Re: [jose] Signature algorithm "none"
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Applications need to define what signature algorithms they accept.   In some cases over some communication channels the signature may not be required.

Applications processing JWT like Connect want to process tokens consistently.  Receiving a JWT with a alg of none is fine under some circumstances.  
In general you would restrict the library from accepting it.  

John B.

On 2013-07-31, at 3:44 PM, Richard Barnes <rlb@ipv.sx> wrote:

> Ok. That seems like a bug in OpenID Connect.  They should be switching the content type (JWS vs. bare request) or using detached signatures.
> 
> What's the result of JWS verification when "alg" == "none"?  It seems like it has to be either "True" or "False".  If you pick "true", there's an easy attack where you just change the algorithm to "none" and delete the signature.  If you pick "false"... well it seems silly to have a signature algorithm that never verifies.
> 
> 
> 
> 
> 
> On Wed, Jul 31, 2013 at 2:48 PM, Mike Jones <Michael.Jones@microsoft.com> wrote:
> It’s optional to sign lots of content.  For instance, OpenID Connect requests can be signed or unsigned, depending upon the security properties desired.  “alg”:”none” is used for such unsigned requests.
> 
>  
> 
>                                                             -- Mike
> 
>  
> 
> From: jose-bounces@ietf.org [mailto:jose-bounces@ietf.org] On Behalf Of Richard Barnes
> Sent: Wednesday, July 31, 2013 5:46 AM
> To: jose@ietf.org
> Subject: [jose] Signature algorithm "none"
> 
>  
> 
> What's the use case for this?  Can we delete it?
> 
> 
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> jose@ietf.org
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