Subject: Re: [bitcoin-dev] [Lightning-dev] Removing the Dust Limit

From: Billy Tetrud <[email-masked]>
Date: Mon, 9 Aug 2021 22:44:04 -0700

For sure, CT can be done with computational soundness. The advantage of
unhidden amounts (as with current bitcoin) is that you get unconditional
soundness. My understanding is that there is a fundamental tradeoff between
unconditional soundness and unconditional privacy. I believe Monero has
taken this alternate tradeoff path with unconditional privacy but only
computational soundness
<https://www.reddit.com/r/Monero/comments/8erg8e/what_should_monero_do_about_the_soundness_problem/dxy59ad?utm_source=share&utm_medium=web2x&context=3>
.

> old things that never move more or less naturally "fall leftward"

Ah yes, something like that would definitely be interesting to basically
make dust a moot point. Sounds like the tradeoff mentioned is that proofs
would be twice as big? Except newer UTXOs would have substantially shorter
proofs. It sounds like the kind of thing where there's some point where
there would be so many old UTXOs that proofs would be smaller on average in
the swap tree version vs the dead-leaf version. Maybe someone smarter than
me could estimate where that point is.

On Mon, Aug 9, 2021 at 10:04 PM Jeremy <[email-masked]> wrote:

> You might be interested in https://eprint.iacr.org/2017/1066.pdf which
> claims that you can make CT computationally hiding and binding, see section
> 4.6.
>
> with respect to utreexo, you might review
> https://github.com/mit-dci/utreexo/discussions/249?sort=new which
> discusses tradeoffs between different accumulator designs. With a swap
> tree, old things that never move more or less naturally "fall leftward",
> although there are reasons to prefer alternative designs.
>
>
>>>