Re: [Taler] A hybrid approach to allow Taler payments at an EMV payment terminal

[Christian Grothoff]

On 6/18/24 09:41, Jaap-Henk Hoepman via Taler wrote:
> On 18/06/2024 09:37, Christian Grothoff wrote:
> > On 6/18/24 07:54, Marc Stibane via Taler wrote:
> > > > and the wallet can be programmed to enforce a maximum balance, to 
> > > > address AML concerns.
> > >
> > > Nope. Open source, anyone could remove the limit.
> >
> > Eh, Free Software. Plus, compliance != security, so having a limit in 
> > the canonical app and in the terms of service _may_ suffice. So this 
> > is really one for actual specialists to figure out, not for us 
> > amateurs to guess around.
>
> If it is relevant for AML, the 'bad people' will try to avoid such a 
> limit; terms of service are irrelevant that category of users ;-) It 
> needs to be strictly enforced by soft- and hardware.

Let me re-iterate this: Compliance != security. Yes, we're both 
professors in info sec, and thus think security. Very natural. But 
possibly totally wrong from a compliance perspective.

To ensure I kind of know what I am doing, I *did* recently take an 
actual AML training for anti-money laundering compliance specialists of 
Swiss financial service providers -- and talked with banks and actual 
lawyers about these things for years now. From what I have learned, you 
are possibly wrong, but as they often say "it depends".

For example, Swiss banks can *today* totally enforce per-customer 
(=human) withdraw limits by sending a PIN/TAN via SMS to a mobile phone 
number. Yes, the bad guys can buy multiple phone numbers. Yes, very bad 
guys can hack SS7 and have as many numbers as they like, or at least 
receive all the SMS they need. It is thus not secure, but nevertheless 
*compliant* according to FINMA. Security is not the objective, so info 
sec professors need to turn off that part of their brain if they want to 
work on compliance.

Plus, remote attestation is evil and Taler must not rely on it as it 
fundamentally violates informational self-determination and we do Free 
Software for a reason.