Re: [OAUTH-WG] JWS Access Token concerns

Sergey Beryozkin <sberyozkin@gmail.com> Tue, 23 February 2016 21:54 UTC

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To: Antonio Sanso <asanso@adobe.com>
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From: Sergey Beryozkin <sberyozkin@gmail.com>
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Date: Tue, 23 Feb 2016 21:54:20 +0000
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Subject: Re: [OAUTH-WG] JWS Access Token concerns
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Hi
On 23/02/16 19:31, Antonio Sanso wrote:
> hi Sergey,
> just my 2 cents
> let’s start from a simple fact that encryption is not authentication. :)
>
And since then the access tokens are supposed to provide the source 
guarantee to the client ? Can you point to any text somewhere suggesting 
the clients must expect the access tokens be a set of JWT JWS signed 
claims ? (lets put the whole PoP aside for now...)

> Now, if the claim sets of a JWS contains only not confidential information JWS is enough.
>
You are right - this is close to what I was asking about. My point is 
that given that a JWS-signed JWT content can be processed as easily as 
Base64 encoded data, the problems will start happening if a given OAuth2 
server inadvertently puts more into this JWT container than it should...

Thanks Sergey

> See also inline
>
>
> On Feb 23, 2016, at 6:15 PM, Sergey Beryozkin <sberyozkin@gmail.com> wrote:
>
>> Hi
>>
>> Some OAuth2 providers may return self-contained access tokens which are JWS Compact-encoded.
>> I wonder is it really a good idea and would it not be better to only JWE-encrypt the tokens. I'm not sure JWS signing the claims is necessarily faster then only encrypting the claims, assuming the symmetric algorithms are used in both cases.
>
> JWE algorithms are all AEAD AFAIK so is not only symmetric encryption plus there is the content key  "wrap algorithm”.
>
> regards
>
> antonio
>
>>
>> For example, my colleague and myself, while dealing with the issue related to parsing an access token response from a 3rd party provider were able to easily check the content of the JWS-signed access_token by simply submitting an easily recognized JWS Compact-formatted value (3 dots) into our JWS reader - we did not have to worry about decrypting it neither the fact we did not validate the signature mattered.
>>
>> But access tokens are opaque values as far as the clients are concerned and if the introspection is needed then the introspection endpoint does exist for that purpose...
>>
>> Thanks, Sergey
>>
>>
>>
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>


-- 
Sergey Beryozkin

Talend Community Coders
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