Re: [Tails-dev] Set coin selection to "privacy" by default i…

Hi,

s7r:
> intrigeri wrote:
> The text was copied from Electrum man page.

Thank you!

> UTXO's are basically the coins you can spend. The spendable coins are in
> UTXO's, not in addresses. Addresses are just a smart crypto way to let
> the world know in advance who has the right to spend a given UTXO.

> Existing unspent outputs cannot be reused, they are burned and re-crated
> entirely every time. So you cannot spend part of a UTXO, you spend it
> all (practice does not recommend re-using addresses - it's true nothing
> keeps you from receiving the change in the same initial address that you
> spent from, but you'll have a different UTXO).

Yes, I had to learn all that last week already, but thanks anyway :)

Still, this doesn't answer my question of why the setting called
'privacy' "helps to reduce blockchain UTXO". I would love to
understand, if someone is kind enough to explain it to me.

>>> Routing transaction relay through Tor is only part of the solution. The blockchain is
>>> a public ledger that can be analyzed anytime after the initial transaction broadcast.
>>> Private coin selection impedes correlation of transaction inputs and outputs that
>>> could link back to an identity.
>>
>> Sure. I hope our doc clearly states that it's very hard to use Bitcoin
>> in a privacy-preserving way, for some various value of "privacy".

> Agreed, but the setting indicated by Michael could be shipped as a
> default imho. It makes sense in a context like Tails/Tor threat model.

Sorry if I was unclear: I'm not arguing this point. I didn't look into
it in details, so I am really not in a position to have opinion about
it yet. It's clear to me that there's no way to optimize coin
selection for all possible desired outcomes (e.g. optimizing the
blockchain itself, optimizing usage of unspent outputs i.e.
not wasting money via fees on the long term, optimizing some kind of
privacy on the short term), but it's not obvious to me which way Tails
should lean towards: at this point I have no idea if the (limited)
privacy benefits brought by this feature outweigh the drawbacks it
brings in other areas.

Anyway: I personally don't feel responsible for maintaining the
Electrum integration in Tails, would rather not to become more
involved into it, and will therefore let its maintainer (i.e. anonym)
make the call. But I'm genuinely curious about the unspent outputs
optimization claim; I bet my intuition is wrong, and I'll learn
something along the way :)

Cheers,
--
intrigeri