Re: [OAUTH-WG] Token Mediating and session Information Backend For Frontend (TMI BFF)

Thanks Warren,

as I see you and Neil have the same idea,
but as of this moment I think this method is not a valid option for
authenticating
a client according to the draft-ietf-oauth-v2-1.

On the other hand, authenticating the client through the BFF
seems conforming to the spec., but in the case when the access token is used
in the browser in fact, I am afraid that it can be regarded as
some kind of "deception" of the AS.

It seems the frontend SPA is not the easiest way to go with oauth...

Stoycho.

On Sun, 14 Feb 2021 at 17:35, Warren Parad <wparad@rhosys.ch> wrote:

> redirect_uri and use PKCE via the code verifier.
>
> Warren Parad
>
> Founder, CTO
> Secure your user data and complete your authorization architecture.
> Implement Authress <https://authress.io>.
>
>
> On Sun, Feb 14, 2021 at 3:51 PM Stoycho Sleptsov <
> stoycho.sleptsov@gmail.com> wrote:
>
>> Thanks a lot for your answer Neil,
>>
>> as I am no expert (yet :-)) in security I was afraid to rely on
>> redirect_uri for authentication of the client,
>> but I will consider that option as more trustworthy now.
>>
>> (it is also not very clear for me which part of the app can be
>> regarded as the redirect_uri owner, the BFF or the loaded frontend
>> SPA, but maybe it is not so important)
>>
>> If you had the two options for authentication of the frontend SPA
>> client - the redirect_uri on the one hand, and the Basic
>> authentication with client secret through the BFF on the other, which
>> one would you recommend?
>>
>> On Sun, 14 Feb 2021 at 16:28, Neil Madden <neil.madden@forgerock.com>
>> wrote:
>> >
>> > Public clients are implicitly authenticated by their ownership of the
>> registered redirect_uri. This why it’s important to use a redirect_uri for
>> which ownership can be reasonably established, such as HTTPS endpoints with
>> exact URI matching.
>> >
>> > There are more things that can go wrong with that (see the security
>> BCP), but it can be made reasonably secure.
>> >
>> > — Neil
>> >
>> > > On 14 Feb 2021, at 13:48, Stoycho Sleptsov <
>> stoycho.sleptsov@gmail.com> wrote:
>> > >
>> > > 
>> > > I would like to add my reasons about the "Why are developers creating
>> BFF for their frontends to communicate with an AS",
>> > > with the objective to verify if they are valid.
>> > >
>> > > I need the client app. to be authenticated at the AS (to determine if
>> it is a first-party app., for example).
>> > > If we decide to implement our client as a frontend SPA , then we have
>> no other option except through a BFF, as PKCE does not help for
>> authentication.
>> > >
>> > > Or is it considered a bad practice to do that?
>> > >
>> > > Regards,
>> > > Stoycho.
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>> >
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