> On 8. Jul 2020, at 23:52, Neil Madden <[email protected]> wrote:
> 
>> 
>> On 8 Jul 2020, at 20:56, Torsten Lodderstedt <[email protected]> wrote:
>> 
>>> Am 08.07.2020 um 20:46 schrieb Neil Madden <[email protected]>:
>>> 
>>> On 8 Jul 2020, at 19:03, Torsten Lodderstedt <[email protected]> 
>>> wrote:
>>>>>> 
>>>>>> What in particular should the use consent with in this step?
>>>>> 
>>>>> “FooPay would like to:
>>>>> - initiate payments from your account (you will be asked to approve each 
>>>>> one)”
>>>>> 
>>>>> The point is that a client that I don’t have any kind of relationship 
>>>>> with can’t just send me a request to transfer $500 to some account. 
>>>> 
>>>> Are we talking about legal consent or a security measures here?
>>> 
>>> Normal OAuth consent. My phone is my resource, and I am its resource owner. 
>>> If a client wants to send payment requests to my phone (e.g. via CIBA 
>>> backchannel) then it should have to get my permission first. Even without 
>>> backchannel requests, I’d much rather that only the three clients I’ve 
>>> explicitly consented to can ask me to initiate payments rather than the 
>>> hundreds/thousands clients my bank happens to have a relationship with.
>> 
>> To me it sounds like you would like to require a client to get user 
>> authorization to send an authorization request. Would you require the same 
>> if I would use scope values to encode a payment initiation request?
> 
> Yes. If something is sufficiently high value to require per-transaction 
> authorization then initiating transactions itself becomes a privileged 
> operation. 

The per transaction authorization alone is a significant increase in security. 
What is the added value of requiring an authorization to send a per-transaction 
authorisation request in an additional step?

> 
>>>> 
>>>> In case of open banking the user legally consents to this process at the 
>>>> client (TPP) even before the OAuth/Payment Initiation dance starts. 
>>> 
>>> How does the bank (ASPSP) confirm that this actually happened?
>> 
>> It does not because it is not the responsibility of the ASPSP. The TPP is 
>> obliged by law to obtain consent.
> 
> If the TPP can be trusted to obey the law about this, why not also trust them 
> to be honest about transactions? Why enforce one thing with access tokens but 
> take the other on trust? Especially as the actual transactions are more 
> likely to have a rigorous audit trail. 
> 
> If we could trust clients to obtain consent we wouldn’t need OAuth at all. 

I thought the same initially, but we must distinguish between legal consent and 
strong authentication/transaction authorization in such a case. Legal consent 
can be obtained in various ways including the traditional OAuth user consent 
but also in other places. Authenticating the user (probably with 2FA) and 
getting authorization for a certain transaction (the meaning of PSD2 SCA) must 
be conducted by the AS. 

> 
> — Neil

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