Re: [Taler] Privacy concerns

[Fabian Kirsch]

Hi Michael,

thanks a lot for going in the related aspects of privacy.

There are two examples you provided:

1.) time correlation. Yes, it would make sense to more prominently warn 
about the consequences if you don't hold reasonable amounts in your 
wallet and therefore need adhoc withdrawels for individual transactions.

2.) value correlations. Similar here, the withdrawels should be managed 
by the privacy-seeking individual in a manner that does not give away 
(too much of) the spending patterns. One possibility would be to make 
withdrawels on regular weekly basis and introduce some random elements 
in the withdrawel amount. But there has to be some at least weak 
feedback of the spending on the withdrawel as that is the primary 
function of money in society. Amount of funds to be hold in TALER can 
then be balanced against gained degree of privacy in a different way by 
every individual.

Together with your points on network privacy:

Taler is meant to be a reliable building block of a society that *wants* 
to implement privacy preserving means of pay.
It is not meant as a grass roots tool to enforce privacy in the face of 
an oppressive environment.
The "T" already acknowledges that the existence of nations is not 
necessarily inherently bad.

Taler was born when public opinion only knew the extremes of total 
transparency (towards some institutions and all crackers owning their 
machines) and total separation from the institutions that society has 
build over time (nations, banks, courts, ..)

Taler will hopefully demonstrate the feasibility of a middle ground, 
which will be adopted by the "good nations".

So far my cents, i am not an official spokesperson of taler.

Fabian


On 05.05.24 21:50, Michael Kohn via Taler wrote:
> Dear colleagues,
>
> the Taler project emphasizes "Privacy".
>
> However, it appears to me that a system like Taler is exactly the opposite.
>
> Currently and for the forseeable future, Banks and payment providers routinely 
> block users that connect through Tor, a VPN or any other anonymizing network 
> provider.
> In the EU it is not possible to obtain an anonymous personal Internet access, 
> either wired or cellular.
> Also, it is - for example - not possible anymore to register even an
> anonymous E-Mail address from any popular E-Mail provider by using an 
> anonymization service or public internet access.
> It is not hard to see that access to banks and payment providers is at least as 
> tightly regulated as access to a free E-Mail account.
>
> Banks and payment providers usually store IP addresses that are related to 
> monetary transactions.
> Governments have easy means, often completely invisible to a citizen and even 
> the network provider, to relate an IP address to a specific person / network 
> provider customer and vice versa.
>
> Thus, while Taler acknowledges that the so-called "merchant" (I do not like this word because it is 
> wrong the way Taler uses it: if one person gives money to another, the receiver does not neccessarily have to 
> be a "merchant"; it is simply not anyone's business why money is transferred between two citizens 
> and it can be transferred for many reason besides merchandise) is not anonymous, the "customer" for 
> all practical purposes will also not be anonymous at all.
>
> For a government, it is quite easy to correlate Person A withdrawing 934,29 
> Euros from Bank A on May 5th, 22:18 by using Taler, and Person B receiving 
> 934,29 Euros on his Account on Bank B on May 5th, 22:19 by using Taler.
>
> Arguing that Taler allows for "anonymous" "customers" is, in the best case, 
> extremely naive and narrows the definition of anonymity down on some crypto specifics of Taler 
> while ignoring the whole bunch of easy identification possibilities of a customer by analyzing bank 
> transfers and/or network accesses.
>
> Governments do have that kind of access to bank and network provider databases 
> since decades.
>
> I'd be happy if there's some hidden gem in the technical details of Taler that 
> I have missed and Taler is indeed truly anonymous for a customer in a REAL 
> WORLD scenario.
>
> What is the threat model of Taler's security and how does it protect  the 
> "customer" (spender) against being identified by a real-world Government, i.e. 
> one that has full acccess to all banking and network provider databases?
>
> Best, Michael