Before (2.0.6):

After (2.0.7):

Easy on the eyes

“Excel sheet” style grids for the transaction history, unused receive addresses, and UTXO menu were simplified into lists with embedded icons. Sharp edges were smoothed out with rounded corners, and text edits were made for extra clarity. But the “UI Refreshment” isn’t just a coat of paint: The pull request implementing it also closed 9 open design issues simultaneously, making Bitcoin privacy smoother than ever.

New buttons

The coinjoin settings can now be accessed from the “. . .” menu in the coinjoin music box, which replaces the blue light that indicated whether the Automatically Start Coinjoin setting was turned on or off. This easy-to-find option makes it convenient to adjust this frequently accessed toolbox.

Speeding up an unconfirmed payment using RBF or CPFP previously required right clicking the entry in your transaction history to find the option. Now, there are visible buttons for getting your pending transactions unstuck or cancelled.

UX improvements

The label for the recipient of an outgoing transaction is now entered on the same screen as the address and amount instead of spawning an extra popup, reducing the process by an additional click.

The Received/Sent/Balance columns in the history were condensed into a single stream of information showing + or – next to transaction amounts. Incoming funds now display a green color for the amount to easily allow viewers to figure out the direction funds are moving.

Don’t be a creature of habit

Many users have feelings of nostalgic regret when the appearance of their favorite app changes, but the UI Refreshment in Wasabi Wallet v2.0.7 is non-invasive to existing workflows. Try the sleek new style of Bitcoin privacy and download today.

The post UI Enhancements in v2.0.7 appeared first on Wasabi Wallet - Blog.

The way this randomness was implemented does not behave like a fair dice, instead, it gives users artificial luck. Random skips occur more frequently while fees are high, and skipping is less likely when fees are low.

How long your wallet waits when skipping rounds is influenced by the coinjoin strategy you choose. There is a different chance to participate in a coinjoin round depending on whether you select “minimize costs”, “maximize speed”, or “maximize privacy”.

The Participation Calculation

The median fee rate of the previous day, week, and month determines the chance of skipping a coinjoin round. This chart shows what percentage of rounds your client will join under each possible combination of fee conditions for each coinjoin strategy profile.

Since the minimize costs strategy uses “weeks” as the coinjoin time preference, there is zero chance of participating whenever fees are higher than the median of the previous day or week. Whenever fees are at the absolute cheapest levels, clients will never choose to gamble away that opportunity and will join 100% of coinjoin rounds.

An additional privacy benefit from random skips is that it staggers the crowd of remixers. Since some users stall in between coinjoins, it increases the likelihood of coinjoining with more unique users as opposed to coinjoining with the same participants of the previous round again.

The subtle privacy fortifications implemented in the Wasabi v2.0.6 release minimize the UX trade-offs with cost or speed that are associated with coinjoins. If you haven’t tried the newest version, don’t skip the upgrade, let the upgrade do the skipping for you!

The post Smart Randomness: Skipping Coinjoin Rounds Based On Fee Rate appeared first on Wasabi Wallet - Blog.

How much privacy should you gain before spending your coins?

Since each coinjoin transaction pays a fee to miners, users have to consider whether the marginal privacy gained from remixing in multiple coinjoins is worth the additional cost. Wasabi’s mission is to provide privacy by default, but users have a limited budget, so a careful balance is necessary.

Coinjoin trilemma concept art – A cost tradeoff is associated with maximizing privacy or speed.

Wasabi users are offered three coinjoin strategies when setting up their wallet: Minimize Costs, Maximize Speed, and Maximize Privacy. The cost and speed strategies will typically complete coinjoining after a single transaction while the privacy strategy will remix multiple times. The exact amount of remixing required before stopping may vary because the outcome of each coinjoin transaction is unique.

Safety for the Hasty

In v2.0.6, Wasabi now considers the abstract quality of privacy for your coinjoin outputs in addition to checking their anonymity score. “Safety coinjoins” are triggered by default to ensure a minimum amount of remixing for users who choose to minimize costs or maximize speed. This feature anticipates how coins might be spent in the future to prevent guesses from being made based on a specific user behaviour. The guessing scenario that safety coinjoins protect against is when a user makes a single deposit, a single coinjoin, and a full withdrawal. Wallets that already have private funds for remixing are already protected, so safety coinjoins only occur when users fund a new wallet.

WabiSabi coinjoins can break the links between your addresses in three different ways:

– Inputs are not linked to other inputs
– Inputs are not linked to outputs
– Outputs are not linked to other outputs

Outputs not being linked to each other can be temporary depending on how those outputs are spent. When outputs from coinjoin transactions are spent together as inputs in a future payment, a definitive link is created between them. However, when coinjoin outputs are spent together as inputs in a future coinjoin, no definitive link is created since coinjoin inputs cannot be linked to other inputs. In order to take advantage of this property, the first deposit made to an empty wallet can only achieve a maximum of 75% privacy progress from its first coinjoin, no matter how high your anonymity score is. Safety coinjoins remix the first set of semi-private outputs that were created from the initial coinjoin round to achieve 100% privacy.

Users sweeping their wallets benefit from the extra safety buffer between the transaction that funds their wallet and the transaction that empties it, preserving the initial privacy gained from splitting into multiple outputs. An observer of a safety coinjoin who is attempting to identify the source of incoming funds based on outgoing amounts is forced to expand their search to include previous coinjoin transactions. Any conclusion drawn by equating similar amounts to each other is broken since private coins exit from a different transaction than the non-private coins entered.

If you haven’t taken the chance to upgrade your privacy yet, download the new 2.0.6 version of Wasabi Wallet and see the safety coinjoin feature in action for your first deposit. 

The post Deeper Privacy with Safety Coinjoins appeared first on Wasabi Wallet - Blog.

Coinjoins are privacy-preserving transactions that contain funds from many users. This operation requires unanimous teamwork: Unless every user signs the transaction, Bitcoin nodes will reject it as invalid, and no privacy progress will be made. This poses a challenge to honest users since there is no cost to an attacker who continuously causes coinjoins to fail, resulting in a denial of service (DoS).

This is where the role of the centralized coinjoin coordinator comes into play. The coordinator acts as a bouncer to exclude known troublemakers, ensuring that honest users are not left waiting indefinitely. ZkSNACKs, which runs the default coordinator for Wasabi Wallet, uses various methods to identify and defeat DoS attacks to improve coinjoin success rates.

First, the economics of Denial of Service attacks are considered. The minimum value allowed to participate in a Wasabi coinjoin is 5000 sats (0.00005000 BTC). When disrupting a coinjoin round, the attack is equally effective whether the missing signature belongs to a low-value input or a high-value input. Due to this threat of an attacker splitting his coins into small pieces, low-value coins are subject to longer bans than high-value coins.

Second, Denial of Service penalty evasion is considered. If a particular address is banned for causing a coinjoin to fail, the attacker can move the coins from the banned address to a fresh address and attempt to register again. To combat this circumvention, bans from previously offending addresses are inherited by the coins they send. This prevents attackers from reusing the same funds for multiple disruptions.

Third, the nature of the offence is considered. There are 3 ways to cause trouble with a coinjoin transaction:

• Register inputs and fail to sign the final transaction
• Double spend a registered input before signing
• Double spend a registered input after signing

Failure to sign may not be intentionally malicious since it can occasionally occur due to limitations of the Tor network’s stability, or because a careless user closes his laptop after the input registration phase. Double spending is prevented by clients and is a clearer indicator of deliberate disruptive activity. The type of offence and the history of previous offences affect how long a coin is banned.

Stability Improvements

When Wasabi 2.0 was first released, Tor was under a network-wide attack that severely degraded its connection reliability. As a result, the coordinator cannot be too strict with bans to prevent Denial of Service since honest users may inadvertently disconnect without signing.

In November 2022, benchmark statistics were measured showing coinjoins would succeed only 10% of the time on the first attempt, and slightly less than 50% on subsequent attempts (known as “blame rounds”). With the v2.0.2.1 release in December, these metrics improved to 15% success on the first attempt.

As a result of months of hard work by the Wasabi and Tor developers, updated statistics from October 2023 show that the overall success rate has more than doubled since the previous year, with over 50% of new rounds and over 80% of blame rounds succeeding. This consistency makes privacy convenient for patience minimalists who quickly tire of the soothing glow of the countdown timer.

Entering the Fee Market

The fee rate of the coinjoin transaction is another variable to account for while waiting for full privacy. The coordinator chooses the mining fee for the coinjoin round before users join, however, fee estimation is not a simple task. On average, a new Bitcoin block is mined every 10 minutes, but there is no way to predict exactly when one will be found or how many new transactions will outbid you until then. 

There are special considerations when choosing the fee rate for coinjoin transactions. Participants often pay several times more in mining fees for a coinjoin transaction compared to a regular payment since they can register multiple inputs and outputs. This increases the marginal advantage for sniping the lowest possible fee rate. In addition, coinjoins are not considered urgent because users are often sending coins to themselves and not to others, so whether or not the transaction is confirmed quickly is not as important because there is no risk that incoming funds will be double spent and lost.

Allowing coinjoin transactions to wait in the mempool also has an unintended privacy benefit. Since unconfirmed coins cannot be registered for new rounds, users who remix their outputs must wait an additional time for their first coinjoin to be mined. By increasing the time period in between consecutive rounds, users are less likely to participate with the same users from their previous round.

Despite these advantages for choosing a low fee, there are also unique reasons for coinjoin transactions that would justify choosing a high fee as a precaution. Users who send a regular payment that gets stuck can easily use Replace By Fee (RBF) to increase its confirmation priority. However, since coinjoins require the cooperation of many users, the first fee is final. There is no way to replicate a higher fee replacement if even a single participant goes offline.

Another reason to prefer a higher fee for coinjoins is because they are disproportionately affected by transaction size limitations in Bitcoin Core’s mempool and block construction logic. Once a chain of transactions spending unconfirmed coins grows too large, nodes will ignore new transactions attempting to build on top of it.

Unfortunately, mining pools have not yet optimized to collect fees from coinjoin transactions. Miners only calculate the single highest-paying descendant transaction package, which may cause them to overlook the confirmation of an extra profitable coinjoin with many spent child outputs.

Patience Preferences

Since it’s impossible to choose a fee that satisfies both the impatient and the thrifty at the same time, Wasabi has a feature called “Coinjoin time preference” to ensure that you don’t get hit with higher than expected mining fees.

If a coinjoin round requires a higher fee than the median of the previous day, week, or month, your client can be configured to skip that round and wait until fees drop or stabilize. This customization gives both spenders and savers flexibility without compromising their preferences or splitting the liquidity pool.

Setting a long coinjoin time preference makes it easy to handle the small coins that accumulate in your wallet as you send and receive transactions. Whenever the best deal on fees becomes available, your wallet will privately consolidate your UTXOs so you can readily spend them when fees increase again.

In conclusion, the combined speed provided by Denial of Service fortification and smart savings from the coinjoin time preference feature has significantly improved Wasabi’s user experience. These advancements and tools have made privacy not only more convenient but also more cost-effective. Coinjoins have never been spicier, try Wasabi Wallet today and join the crowd.

The post Time is Money: DoS (Denial of Service) Fortification and Coinjoin Time Preference appeared first on Wasabi Wallet - Blog.

Although Bitcoin makes for a generous gift, you might be giving away more than you realize when making a transaction. Because Bitcoin is a public ledger, the addresses that sent you money become known by the addresses you sent the money to next.

In this blog post, we’ve outlined a few simple steps to send Bitcoin anonymously with Wasabi Wallet – a surefire way of upgrading your gift-giving skills and orange-pilling your family and friends.

Step 1

If you are using Bitcoin privately for the first time, download Wasabi and write down your wallet recovery words on a sheet of paper.

Step 2

Choose a password that you will not forget for your wallet. You will enter your password later in order to send your gifts, and there is no way to recover your password.  Next, choose your highest priority for coinjoins:  Savings, Speed or Privacy.

Step 3

Create a new address for receiving the Bitcoins you want to make private. Wasabi requires you to make a note to remind yourself who sent these coins to you in order to help you keep track of your privacy.

Step 4

After you have BTC in your wallet, the coinjoin box and privacy progress bar will appear. Coinjoins will not start automatically for amounts under 0.01 BTC in order to save mining fees, but you can click play to start coinjoining any amount over 0.00005000 BTC.

Step 5

The box at the bottom of the screen tracks the stages of the coinjoin signing process. All you have to do is sit back and wait while your coins are being bundled with other Wasabi users.

Step 6

After the coinjoin finishes, you will see your privacy progress has increased. Click the green bar to see the value and anonymity score of the inputs in your wallet.

Step 7

Now, you can send the gift of Bitcoin privately to your family member and the gift’s recipient can not be tracked by the exchange or customer you originally received your Bitcoin from!

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