如果可以,請跟踪我 - 如何 Bitcoin 前瞻性匿名設置工作

By Bitcoin 雜誌 - 1 年前 - 閱讀時間:13 分鐘

如果可以,請跟踪我 - 如何 Bitcoin 前瞻性匿名設置工作

Whirlpool gives a certain level of privacy when using bitcoin, and forward-looking anonymity sets are a measure of how well hidden you are.

讓我們來談談惠而浦的“前瞻性匿名群體”——你躲藏在其中的人群。

迄今為止,您可能熟悉 Whirlpool CoinJoin 實現,該實現可在 Samourai錢包 移動應用程序,或 麻雀錢包 desktop app. When you participate in a Whirlpool CoinJoin you gain privacy by collaborating in a multiparty transaction which leaves anyone looking on-chain scratching their head while trying to decipher where your bitcoin 走了。

A Whirlpool CoinJoin is just like any other bitcoin transaction, made up of inputs and outputs. However each input is provided by a different bitcoin wallet, and each output is returned to one of the participating wallets. This transaction is organized by Samourai Wallet’s central Whirlpool coordinator, all the time without the coordinator knowing which input belongs to which output (“blinded”), and without you ever giving up custody of your bitcoin.

Let’s say it’s the end of the month and I’ve just been paid by my employer. Before I spend any of my bitcoin I first wish to use Whirlpool to gain some forward-looking privacy. After all, the bitcoin blockchain is a public ledger and I feel it my right for my employer to not know what I get up to in my private life, including them knowing my spending habits.

我進入 Whirlpool,提供其中一個輸入並參與如下所示的交易:

5 x Input UTXOs.5 x Output UTXOs. Each input UTXO belongs to one of the five participating wallets.Each output UTXO belongs to one of the five participating wallets. All output UTXOs are equal.

在鏈上觀察無法確定五個輸出中哪一個是我的。 之所以“不可能”,是因為交易的輸入端和輸出端之間的所有確定性鏈接都被打破了。 因此,如果我偷偷摸摸的雇主決定在我發工資後試圖監視我的消費習慣,他們會看到我“進入”惠而浦,現在不得不假設我躲在五個人的人群中,正確的? 好吧,我實際上可能躲在超過五個人的人群中。 輸入惠而浦前瞻性匿名集……

惠而浦前瞻性匿名套裝

When you use Whirlpool, depending on the pool size you choose, your bitcoin is broken up into smaller pieces in one of the following denomination sizes: 0.5 BTC, 0.05 BTC, 0.01 BTC, or 0.001 BTC. Due to Whirlpool’s architecture, outputs which remain in these pool denomination sizes are free to be remixed at no additional cost to the user (more on that later).

在我第一次混音之後,如果我或我的混音同行重新混音,我隱藏的人群(前瞻性匿名組)就會從五個增加到九個。

我的同等輸出 UTXO 不需要為我躲藏成長的人群重新混合。 無論是我的 UTXO 進行重新混合,還是我的一個混合對等體,都無法在鏈上判斷第一個混合中的哪個 UTXO 已被重新混合。 現在有九個相同的輸出連接到我的第一個組合,所以我的間諜雇主必須假設我可能是其中任何一個。

下一張圖展示了我隱藏的人群如何在沒有我重新混音的情況下增長。 在我第一次混合後,我的 UTXO(紅色圓圈)仍保留在 Whirlpool 池面額大小中,並且尚未重新混合。 然而,我的兩個混音同行繼續重新混音,現在還有四個與我的第一次混音相關的 CoinJoins。 為了計算我的新的前瞻性匿名集,我在這裡計算了等輸出 UTXO(橙色圓圈)加上我自己的等輸出 UTXO(紅色圓圈),然後我得到了 21 個人群。

在鏈上,橙色圓圈與我的紅色圓圈沒有區別,因此,如果我的雇主希望在“進入”惠而浦後追踪我,他們將不得不追踪所有 21 個不同的線索。 即使他們試圖密切關注,他們也無法確定我是 21 個 UTXO 中的哪一個。

混音如何免費?

在進一步討論前瞻性匿名集並查看一些現實世界的示例之前,對於外行來說,有必要詳細解釋一下 Whirlpool 中的混音是如何免費的。

當您第一次“進入”Whirlpool 時,您的 Samourai 或 Sparrow 錢包會廣播所謂的“交易零”,簡稱 Tx0。 這是“跳入池子”之前的預交易,它做了三件事:

預混合 UTXO/s: breaks up your bitcoin into smaller-denomination UTXOs, plus a little extra.固定池費:向 Samourai 或 Sparrow 錢包支付協調 Whirlpool 交易的費用。多克西變化: returns to you any bitcoin which is too small to be mixed. This is called doxxic as it is still associated with the previous history your bitcoin has.1

在以下區塊瀏覽器中查看這個現實世界的 Tx​​0:

Transaction ID: bcb4d9dfde37215f2ede6142c651981e22f70e549c03cd341a71dffe8b2dce57

kycp.org oxtme (double-click on the blue circle to expand the transaction, then zoom out)內存池

在下圖中,請注意,在此 Tx3 中創建了 0 x 預混合 UTXO,所有這些都歸同一個錢包所有,並且注定要在 0.001 池中混合。 另請注意,每個 UTXO 的價值都比所選池大小稍高。 保持這個想法!

It’s worth mentioning here a highly important aspect of a Tx0; management of Doxxic change. Doxxic change is your bitcoin which still holds any previously associated history, however is too small to be Whirlpooled1. The Tx0, by design, returns the Doxxic change to a different area in your wallet than your bitcoin which has been mixed. This means it is impossible to shoot yourself in the foot by accidentally creating a transaction in the future where you spend your mixed bitcoin in the same transaction as your Doxxic change. Doing so would unwind the privacy benefits of CoinJoining.

現在您已準備好進行混合。 Whirlpool 協調員會逐一選擇您的預混合 UTXO 來參與他們的第一次 CoinJoin。 您的預混合 UTXO 之一將是 CoinJoin 交易中的五個輸入之一。

The Whirlpool coordinator also organizes a second pre-mix UTXO to participate (“peer pre-mix UTXO”)2. This additional peer pre-mix UTXO is from another user’s wallet which has just gone through the same process you have when you entered Whirlpool. Remember how when you create your transaction zero your bitcoin is broken up into multiple pool-size denominated UTXOs, plus a little extra? Well if you add up the “little extra” of the pre-mix UTXO and the peer pre-mix UTXO, that is what pays the miner fees for the CoinJoin transaction. In the graphic below the amount to be paid to the bitcoin miners is 907 sats plus 907 sats, totaling 1,814 sats.

現在是混音器大放異彩的時候了。 Whirlpool 協調員隨機選擇三個已經進行了第一次混合的重新混合 UTXO。 這三個重新混合的 UTXO 位於各自的錢包中,重要的是仍保留在 Whirlpool 的“未使用容量”中,因為它們尚未被其所有者使用。 只要他們的關聯錢包與 Whirlpool 協調員在線通信,他們就有資格進行重新混合。

回顧一下:

Your pre-mix UTXO: pays for CoinJoin miner feesPeer pre-mix UTXO: pays for CoinJoin miner feesRemixing UTXOs: participates in the CoinJoin for free (also termed a “freerider”)

Once the CoinJoin has been organized between five separate wallets, the transaction is broadcast to the Bitcoin network automatically. Five inputs into the transaction have been destroyed, creating five fresh indistinguishable equal outputs. All equal outputs are now eligible for remixing if their owners so please.

儘管重新混合UTXO 被稱為“搭便車者”,但它們是Whirlpool 架構不可或缺的一部分,不僅為支付CoinJoin 交易礦工費用的預混合者提供前瞻性匿名性,而且還增加了為其預混合器設置的前瞻性匿名性。以前的混合同行。

同樣重要的是要注意,您的 UTXO(無論是預混合的還是重新混合的)將始終混合在自己的 CoinJoin 交易中。 您錢包中的多個 UTXO 永遠不會在同一個 Whirlpool CoinJoin 交易中混合在一起,因為這提供了最佳的非設定保證,並且還可以防止用戶或實體 Sybil 攻擊 Whirlpool。

TLDR:“進入”惠而浦的新流動性涵蓋了每筆惠而浦 CoinJoin 交易的挖礦費用。 那些已經“進入”Whirlpool 並進行第一次混合(支付固定池費加礦工費)的 UTXO,只要保持其池面額大小/未使用容量,就不需要再支付一聰的費用來參與混音。

惠而浦前瞻性匿名集(續)

理論固然很好,但作為 Whirlpool 用戶,您如何計算您隱藏的人群規模? 嘗試使用 OXT 的交易圖可視化工具 搜索您的第一筆混合 CoinJoin 交易,然後:

Manually expand each output which is remixed.Mark in orange any UTXO which is unspent (remaining in a Whirlpool pool-size denomination).Mark in orange any UTXO which is spent (leaving Whirlpool).

將橙色線相加即可獲得前瞻性匿名集(在下面的示例中為 33)。

This works well for smaller numbers, but Whirlpool mixes occur frequently (average of 211 mixes per day in the 0.001 pool so far during 2022). Manually counting forward-looking anonymity sets can quickly become impossible. Queue Whirlpool Stat Tool ...

Whirlpool Stat Tool

Whirlpool 統計工具 was made by the Samourai Wallet developers to allow users to verify themselves the anonymity sets which are achieved by using Whirlpool. Using a set of python scripts, it quickly calculates the forward-looking anonymity set for you. Enter in a transaction ID for your first mix and it'll tell you the size of the crowd you're hiding in since your Whirlpool CoinJoin occurred.

因為我運行一個 RoninDojo節點,Whirlpool 統計工具已預安裝,並且按照其指南即可輕鬆使用 維基.

在過去 93 天中,我一直在使用該工具監控此 Whirlpool CoinJoin 交易 ID 的前瞻性匿名集:

1fed0d526e89cd3f2ac14be0cfc1fe13e5cb8a772977551f0922f0c6907ab8f3

Let's see how large the crowd its participants are hiding in is:

混合後 28 天:前瞻性匿名集 = 1,644

混合後 35 天:前瞻性匿名集 = 6,722

混合後 93 天:前瞻性匿名集 = 35,214(如下面我的 RoninDojo 上的 Whirlpool 統計工具所示)。

Hiding in a crowd of 35,000 it is now impossible (dare I say it) for anyone, including a chain surveillance company, to determine where the original mix participant's bitcoin is. Perhaps they've already left Whirlpool and spent their bitcoin, or maybe they have stuck around to get free remixes.

我對這個特定的交易 ID 感興趣的是,截至撰寫本文時, 其中一項產出仍未使用 (就像之前圖形中的紅色圓圈一樣)。 自 728,735 年 24 月 2022 日交易被確認到區塊 XNUMX 以來,這種未花費的產出一直保持這種狀態。

Even though this UTXO has not moved, it has benefited from Whirlpool's architecture as three of the other participants went on to remix. This allowed this unspent output of 0.001 BTC to gain a larger forward-looking anonymity set without remixing itself. If none of the outputs from this transaction went on to remix, the forward-looking anonymity set would remain at five.

It's important to remember that all deterministic links are broken after one mix, but you get greater privacy benefits if you, or other peers remix. Let’s look at some more forward-looking anonymity set stats from some CoinJoins ...

更多惠而浦前瞻性匿名集示例

交易編號:
c0f11a33a3f2470bb4252c155ced5eb670aaf0ed2f0eef8674dc90c52905860d
混合後兩天:前瞻性匿名集 = 77

交易編號:

5f5631356692b4744413a61b4e91c41c3df5ae376b66990052a8628b570e8353
混合後 380 天:前瞻性匿名集 = XNUMX

交易編號:

901f20a383189c496a8774eb8cafeaa956f8c3393ee41701f163c0c2acf54286

混合後十天:前瞻性匿名集 = 1,466

隱私農業

進入 Whirlpool 後,您的第一次混合很快,並且您參與的 CoinJoin 已按照設計工作,打破了所有確定性鏈接。 現在,您渴望獲得一些免費混音,但想知道“一周內我可以期待多少次混音?” 這是 Whirlpool 新用戶提出的一個常見問題,他們天真地只根據每個 UTXO 參與的混合週期來計算隱私收益。

重新混合當然會增加您自己的前瞻性匿名集,但不要忘記其他重新混合的同行也會增加您的前瞻性隱私。

“但是一周內我可以期待多少次混音?!” 在回答之前,我們需要考慮以下幾點:

New users who enter Whirlpool pay for the CoinJoin cycle. So only when new liquidity comes into Whirlpool do you have a chance at remixing.Other users (“freeriders”) are also waiting to get free remixes. The Whirlpool coordinator selects freeriders at random to participate in remixes, so there is somewhat of a competition as everybody wants to be picked.Each Whirlpool pool size has different behavior characteristics.

我們來一一探討一下。

以下是 2022 年每個池大小的每週 CoinJoin 週期頻率。

毫不奇怪,0.001 BTC 礦池是周期計數最活躍的礦池。

每個池中有多少自由騎手比賽? 要獲取此統計數據(以及許多其他統計數據,包括循環頻率),您可以使用 電報旋轉機器人.

For each CoinJoin the Whirlpool coordinator picks three freeriders at random to participate.2

作為自由騎行者,較小池中的競爭更加激烈,CoinJoin 週期也更加頻繁。 較大的礦池則相反,自由競爭較少,CoinJoin 週期也較少。

最後,讓我們根據 Whirlpool 的歷史使用情況來思考每個池的行為特徵。 如果您已經成為惠而浦用戶一段時間,您可能會注意到較小的池在日常使用中最為一致,並且具有穩定的流動性。 如果我猜的話,這是因為它們的進入門檻最低,而且最有可能用於日常支出。 另一方面,較大的資金池雖然幾乎從不安靜,但會看到新流動性的更大的波峰和波谷——而且當下雨時,傾盆大雨。

現在您明白了,您在一周內看到的混音取決於進入 Whirlpool 的新流動性、協調員的隨機選擇以及您所使用的資金池規模的特徵。 根據 2022 年迄今為止 Whirlpool 的平均使用情況,您的錢包可能每週會收到 5-25 次混音。 儘管協調員的選擇是隨機的,所以理論上你可以得到更少或更多,但這仍然被歸類為正常。

One way to consider all of this is that awaiting remixes is like yield farming for bitcoin privacy, and those who are patient and continue to keep their bitcoin remixing until they need to spend in the future are being paid interest in the form of increased anonymity. Patience pays.

有資格 24/7 進行混音

要成為一名搭便車者,您需要您的錢包與 Whirlpool 協調員 24/7 保持聯繫。 這樣,當混音即將發生時,您就有機會被協調員挑選為混音師。 因此,您需要執行以下操作之一:

讓 Whirlpool 服務屏幕在您的設備上保持打開並處於活動狀態 Samourai 錢包移動應用. This is the least practical and some Android devices can kill background services, so some but not all users have positive results achieving remixes this way.Run the Whirlpool GUI 桌面應用程序 on your computer (linked to your Samourai Wallet). This is by far the lowest barrier to entry option for Samourai users, and has greater reliability for connections over the Tor network. By leaving your computer turned on, with the Whirlpool GUI desktop application running, you’re eligible for remixing.Run a RoninDojo節點. After linking your Samourai Wallet to your node’s backend, you can turn off your phone or computer and you’ll always be eligible for remixing. A slightly larger barrier to entry, but the benefits far outweigh the hurdles.Mix on the Sparrow 錢包桌面應用程序。 Sparrow 於 2021 年 XNUMX 月將 Whirlpool 集成到其錢包軟件中,與 Samourai Wallet 用戶共享相同的流動性池。 Sparrow 具有豐富的其他功能,還允許您混合到冷藏。 為了獲得重新混合的資格,請確保您的計算機保持運行狀態並運行 Sparrow 應用程序。

惠而浦未使用產能:惠而浦成功的真正衡量標準?

Whirlpool unspent capacity is the current amount of bitcoin which has mixed, not been spent and is eligible for remixing. You can monitor this metric in 克拉克穆迪的儀表板:

您還可以使用以下命令獲取每個池大小的未使用容量的詳細信息: Bitcoin 關鍵績效指標 website. To me the Whirlpool unspent bitcoin value is interesting, and with it remaining above 4,000 BTC for the last seven months shows a level of confidence in Whirlpool and Samourai/Sparrow’s wallet software. What I find more interesting is the volume coming in and out of Whirlpool over the last 30 days (shown in Clark Moody’s dashboard as “Tx0 Volume” and “Spent Cycle Output” respectively). This is what feeds the privacy gains that Whirlpool provides, for both the new liquidity entering, and the freeriders remixing, even if there is a deficit between the two values. Samourai Wallet is branded “a bitcoin wallet for the streets,” and their founders are advocates of actually using bitcoin rather than “HODLing to the grave.” Monitoring these large flows of bitcoin go in and out of Whirlpool shows there is demand for forward-looking privacy when making on-chain transactions, of which Whirlpool is successful in achieving for its users.

Care About Your Bitcoin Privacy? Read More

漩渦你的最簡單的方法 Bitcoin 並保護隱私 - Bitcoin Magazine article by Econoalchemist.

Bitcoin Privacy Series – 七個簡短的介紹視頻。

理解 Bitcoin Privacy with OXT – 由四部分組成的系列文章。

尾注:

1. 為了在本文中描述漩渦流,這一點已被簡化。 如果您嘗試匯入 Whirlpool 的金額超過 Whirlpool 協調員強制執行的最大限額,則找零也可能會退還給您。 扣除協調池費用輸出後,0.001 BTC 池具有 25 x UTXO 最大 Tx0 限制,0.01 BTC / 0.05 BTC / 0.5 BTC 池具有 70 x UTXO 最大 Tx0 限制。

2. 為了在本文中描述漩渦流,這一點已被簡化。 雖然 Whirlpool CoinJoin 交易最常見的是由兩個預混合 UTXO 組成,但 Whirlpool CoinJoin 交易也有可能由三個預混合 UTXO 組成。

This is a guest post by Brother Rabbit. Opinions expressed are entirely their own and do not necessarily reflect those of BTC Inc. or Bitcoin 雜誌。

原始來源: Bitcoin 雜誌