[bitcoin-dev] Wasabi Wallet 2.0 Testnet Release

[bitcoin-dev] Wasabi Wallet 2.0 Testnet Release

[Max Hillebrand]

Hello list,

tl;dr: we have been working on a little something, and Wasabi 2.0 is now 
ready for your review and feedback.

Wasabi Wallet 2.0 is a Bitcoin wallet providing effortless privacy for 
its users. Just like Wasabi 1.0, this is achieved by default on the 
network layer with a deep Tor integration, and on the synchronization 
layer with BIP158 block filters or the packaged Bitcoin full node. 
However, 2.0 upgrades the privacy on the blockchain layer with a new 
Wabisabi coinjoin implementation, running by default in the background.

Wabisabi is a drop-in replacement for the ZeroLink coinjoin coordination 
protocol. Instead of Chaumian [or Schnorr] blind signatures, it uses 
keyed verified anonymous credentials and Pedersen commitments. This 
enables anonymous DoS protection for centrally coordinated coinjoins 
without relying on equal amount outputs. This flexibility in the 
coordination enables a more sophisticated amount decomposition, 
specifically with standard denominations of low Hamming weight, in our 
case powers of two, powers of three, and the preferred value series [1, 
2, 5]. In our simulations, this results often in "changeless" coinjoins 
[all outputs at least two anonymity set, aka count of equal value 
outputs] for transactions with more than 50 inputs. Whereas in Wasabi 
1.0 each user had to participate in the smallest standard denomination 
of 0.1 btc, now there is no mandatory output decomposition, and the 
minimum amount is 5000 sats. This is **substantial** block space 
savings, reducing the amount of mining fees paid, and the time until the 
user's utxo set is private.

Thanks to these efficiency improvements, we are now comformaking 
coinjoin transactions the default in Wasabi's UX. As soon as bitcoin is 
received in the wallet, the client will register the confirmed coin as 
input for the PSBT with the backend coordinator. Within a couple hours, 
the user has numerous utxos which can be spent privately without 
revealing their pre-mix transaction history. The resulting UX is simple: 
receive, wait, spend. Privately. Effortless. For everyone.

Whenever the user wants to spend bitcoin to an address, the wallet 
automatically selects those private coins with sufficient sats, coin 
control is displayed to the user. However, when the private balance is 
insufficient to make the payment, the user has the option to adjust the 
coin selection with the help of the previously provided contact labels. 
Since labeling is mandatory in Wasabi, we can abstract away the utxo 
concept and display only the contact labels for the users to choose 
from. Wasabi also suggests the user to slightly adjust the payment 
amount so as to avoid the creation of a change utxo, decreasing fees and 
improving future privacy.

Today, we are proud to finally reveal our work in progress in a public 
preview release with coinjoin on testnet. We kindly ask for your help 
testing the completely new UI/UX, reviewing the cryptography and 
coordination protocol, and especially coinjoining to analyze the 
resulting transaction graph in the wild.

Thank you to all contributors past and present!

Skol
Max Hillebrand

Download the testnet release: 
https://github.com/zkSNACKs/WalletWasabi/releases/tag/v1.98.0.0

Website: https://wasabiwallet.io
Onion: http://wasabiukrxmkdgve5kynjztuovbg43uxcbcxn6y2okcrsg7gb6jdmbad.onion
Testnet coordinator: 
http://testwnp3fugjln6vh5vpj7mvq3lkqqwjj3c2aafyu7laxz42kgwh2rad.onion

Re: [bitcoin-dev] Wasabi Wallet 2.0 Testnet Release

[nopara73]

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The first Wasabi Wallet 2.0 testnet coinjoin with real users:
https://blockstream.info/testnet/tx/68849dc71e6eb860b4b8aa3f57b9bc8178a002b54f85a46305bfaaad28b40444

On Tue, Mar 1, 2022 at 11:27 PM Max Hillebrand via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Hello list,
>
> tl;dr: we have been working on a little something, and Wasabi 2.0 is now
> ready for your review and feedback.
>
> Wasabi Wallet 2.0 is a Bitcoin wallet providing effortless privacy for
> its users. Just like Wasabi 1.0, this is achieved by default on the
> network layer with a deep Tor integration, and on the synchronization
> layer with BIP158 block filters or the packaged Bitcoin full node.
> However, 2.0 upgrades the privacy on the blockchain layer with a new
> Wabisabi coinjoin implementation, running by default in the background.
>
> Wabisabi is a drop-in replacement for the ZeroLink coinjoin coordination
> protocol. Instead of Chaumian [or Schnorr] blind signatures, it uses
> keyed verified anonymous credentials and Pedersen commitments. This
> enables anonymous DoS protection for centrally coordinated coinjoins
> without relying on equal amount outputs. This flexibility in the
> coordination enables a more sophisticated amount decomposition,
> specifically with standard denominations of low Hamming weight, in our
> case powers of two, powers of three, and the preferred value series [1,
> 2, 5]. In our simulations, this results often in "changeless" coinjoins
> [all outputs at least two anonymity set, aka count of equal value
> outputs] for transactions with more than 50 inputs. Whereas in Wasabi
> 1.0 each user had to participate in the smallest standard denomination
> of 0.1 btc, now there is no mandatory output decomposition, and the
> minimum amount is 5000 sats. This is **substantial** block space
> savings, reducing the amount of mining fees paid, and the time until the
> user's utxo set is private.
>
> Thanks to these efficiency improvements, we are now comformaking
> coinjoin transactions the default in Wasabi's UX. As soon as bitcoin is
> received in the wallet, the client will register the confirmed coin as
> input for the PSBT with the backend coordinator. Within a couple hours,
> the user has numerous utxos which can be spent privately without
> revealing their pre-mix transaction history. The resulting UX is simple:
> receive, wait, spend. Privately. Effortless. For everyone.
>
> Whenever the user wants to spend bitcoin to an address, the wallet
> automatically selects those private coins with sufficient sats, coin
> control is displayed to the user. However, when the private balance is
> insufficient to make the payment, the user has the option to adjust the
> coin selection with the help of the previously provided contact labels.
> Since labeling is mandatory in Wasabi, we can abstract away the utxo
> concept and display only the contact labels for the users to choose
> from. Wasabi also suggests the user to slightly adjust the payment
> amount so as to avoid the creation of a change utxo, decreasing fees and
> improving future privacy.
>
> Today, we are proud to finally reveal our work in progress in a public
> preview release with coinjoin on testnet. We kindly ask for your help
> testing the completely new UI/UX, reviewing the cryptography and
> coordination protocol, and especially coinjoining to analyze the
> resulting transaction graph in the wild.
>
> Thank you to all contributors past and present!
>
> Skol
> Max Hillebrand
>
> Download the testnet release:
> https://github.com/zkSNACKs/WalletWasabi/releases/tag/v1.98.0.0
>
> Website: https://wasabiwallet.io
> Onion:
> http://wasabiukrxmkdgve5kynjztuovbg43uxcbcxn6y2okcrsg7gb6jdmbad.onion
> Testnet coordinator:
> http://testwnp3fugjln6vh5vpj7mvq3lkqqwjj3c2aafyu7laxz42kgwh2rad.onion
>
>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>


-- 
Best,
Ádám

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Re: [bitcoin-dev] Wasabi Wallet 2.0 Testnet Release

[Prayank]

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Hi Max,

> Whenever the user wants to spend bitcoin to an address, the wallet automatically selects those private coins with sufficient sats, coin control is displayed to the user.

1.There are no 'private' coins. Every coin is public in Bitcoin.

2.Since, the wallet assumes some coins as 'private' based on certain things it can be misleading for the user. Privacy depends on the things users want to share with others.

3.There is no coin control in Wasabi Wallet 2. 

> However, when the private balance is insufficient to make the payment, the user has the option to adjust the coin selection with the help of the previously provided contact labels.

User does not select coins because they are never shared with the user in the first place.

[Selecting some labels][1] with misleading text 'who can see this transaction' does not look helpful.

> Wasabi also suggests the user to slightly adjust the payment amount so as to avoid the creation of a change utxo, decreasing fees and improving future privacy.

Privacy involved in using a change or not using it is debatable. Not using a change address makes it easier to understand who might be the recipient in a transaction whereas using a change address same as other outputs would be difficult to analyze for possible recipients.

Wasabi wallet does not have different types of addresses to use for a change however [Bitcoin Core][2] recently made some related improvement which would improve privacy.

> We kindly ask for your help testing the completely new UI/UX

As WW2 is not developed for power users (mentioned by developers working on Wasabi), I am not sure if bitcoin dev mailing list would be the best place to look for newbies. As far as issues are concerned, there are several things not fixed and shared in different GitHub issues or discussions. These include privacy, security and other things.


[1]: https://i.imgur.com/Gxjmhau.png
[2]: https://github.com/bitcoin/bitcoin/pull/23789


-- 
Prayank

A3B1 E430 2298 178F

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Re: [bitcoin-dev] Wasabi Wallet 2.0 Testnet Release

[nopara73]

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>  There is no coin control in Wasabi Wallet 2.

This is correct, but in and of itself can be misleading for those who know
that privacy in Bitcoin is near impossible without coin control, because
the conclusion would be then that Wasabi 2.0 ruined privacy for no reason,
which is obviously not the case, in fact it improves it in many ways.

The idea is that you don't need coin control when you can make your
transaction with coinjoined coins. These coins are indistinguishable, so
you don't really have a use for coin control in that case. I think this is
non-controversial, but what about the case when you cannot make the tx from
coinjoined coins?

In that case there still is a mandatory privacy control, which is an
improved version of coin control. The insight here is that, in coin control
settings, users are differentiating between coins based on their labels.
Since Wasabi creates label clusters, it is ok to select the clusters the
user wants to make the transaction from instead of individual coins. I know
you liked the never released cluster selection page before it got further
improved to be a privacy control page, but note the privacy control still
uses the same insight, it just further removed unnecessary friction. That
being said, coins can also be seen with this super secret developer key
combination: CTRL + D + C

> User does not select coins because they are never shared with the user in
the first place.

As explained above it is selecting coins indirectly rather than directly.
It is selecting clusters of coins that are assumed to belong to the same
wallet from an outside observer's point of view instead of individually
selecting coins one by one.

>  There are no 'private' coins. Every coin is public in Bitcoin.

Not sure I'd like to engage in bikeshedding on terminology, but in my
opinion this terminology is not only true, but also good and useful:
Ownership of equalized coinjoin UTXOs is only known by the owner and not by
external observers. The owner has control over who it reveals the ownership
of these UTXOs. Privacy is your ability to selectively reveal yourself to
the world, therefore the terminology of "private coins" naturally makes
sense and it's a useful differentiator from non-coinjoined coins.

>  Since, the wallet assumes some coins as 'private' based on certain
things it can be misleading for the user. Privacy depends on the things
users want to share with others.

The wallet does not assume. The user assumes when selecting the anonymity
levels. The wallet works with the user's assumption of its threat model. If
a misleading claim can be made here then it's that the user misleads the
wallet (and her/himself) rather than the other way around.

>  Privacy involved in using a change or not using it is debatable. Not
using a change address makes it easier to understand who might be the
recipient in a transaction whereas using a change address same as other
outputs would be difficult to analyze for possible recipients.

Although I agree it's debatable, but for different reasons. I'd rather take
an issue of its usefulness instead. About the assumption that it's easier
to understand who might be the recipient, that's incorrect as the
transaction can easily be considered a self spend. In comparison to change
generating transactions, there the change and the recipient can most of the
times be established.

>  Wasabi wallet does not have different types of addresses to use for a
change however [Bitcoin Core][2] recently made some related improvement
which would improve privacy.

Yup. Unfortunately this is a hack to make the wallet feel like a light
wallet as it greatly reduces the size of the client side filters we have.
Although, as the blockchain grows further optimizations are needed. So it's
not very helpful if Bitcoin Core gives us 10 GB of filters so we can use
all the types of addresses. We had a pull request to Core about creating
custom filters, but it was NACK-ed. In order to do this correctly and get
merged into Core we'd have to have a more comprehensive modification than
our initial PR and that we have no resources to allocate to yet.

>  As far as issues are concerned, there are several things not fixed and
shared in different GitHub issues or discussions. These include privacy,
security and other things.

I greatly disagree with this assessment, in fact, quite the opposite. Take
for example the tremendous activity your pull request about an empty catch
block received: https://github.com/zkSNACKs/WalletWasabi/pull/6791
No sane project would allow their best developers to spend more than 5
minutes on this issue, yet 7 developers were discussing if leaving a single
empty catch block in the code could be a potential security risk in the
future and our resolution was actually contributing to NBitcoin to make
sure we aren't getting an exception for incorrect password, but rather a
boolean signal.

>  As WW2 is not developed for power users (mentioned by developers working
on Wasabi), I am not sure if bitcoin dev mailing list would be the best
place to look for newbies.

I do agree that the bitcoin-dev mailing list is not where the target users
of Wasabi 2.0 are to be found, however Wasabi 2.0 is a great forward step
of Bitcoin development and developers could certainly benefit from knowing
about great innovations it comes with.

On Wed, Mar 9, 2022 at 5:27 PM Prayank via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Hi Max,
>
> > Whenever the user wants to spend bitcoin to an address, the wallet
> automatically selects those private coins with sufficient sats, coin
> control is displayed to the user.
>
> 1.There are no 'private' coins. Every coin is public in Bitcoin.
>
> 2.Since, the wallet assumes some coins as 'private' based on certain
> things it can be misleading for the user. Privacy depends on the things
> users want to share with others.
>
> 3.There is no coin control in Wasabi Wallet 2.
>
> > However, when the private balance is insufficient to make the payment,
> the user has the option to adjust the coin selection with the help of the
> previously provided contact labels.
>
> User does not select coins because they are never shared with the user in
> the first place.
>
> [Selecting some labels][1] with misleading text 'who can see this
> transaction' does not look helpful.
>
> > Wasabi also suggests the user to slightly adjust the payment amount so
> as to avoid the creation of a change utxo, decreasing fees and improving
> future privacy.
>
> Privacy involved in using a change or not using it is debatable. Not using
> a change address makes it easier to understand who might be the recipient
> in a transaction whereas using a change address same as other outputs would
> be difficult to analyze for possible recipients.
>
> Wasabi wallet does not have different types of addresses to use for a
> change however [Bitcoin Core][2] recently made some related improvement
> which would improve privacy.
>
> > We kindly ask for your help testing the completely new UI/UX
>
> As WW2 is not developed for power users (mentioned by developers working
> on Wasabi), I am not sure if bitcoin dev mailing list would be the best
> place to look for newbies. As far as issues are concerned, there are
> several things not fixed and shared in different GitHub issues or
> discussions. These include privacy, security and other things.
>
>
> [1]: https://i.imgur.com/Gxjmhau.png
> [2]: https://github.com/bitcoin/bitcoin/pull/23789
>
>
> --
> Prayank
>
> A3B1 E430 2298 178F
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>


-- 
Best,
Ádám

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