Coinjoiner

A WabiSabi coordinator which aims to improve Bitcoin privacy

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What is Coinjoiner?

Coinjoiner is an attempt to drive Bitcoin privacy towards more resilience and robustness.

How to connect

You can copy the following string and open your Wasabi Wallet: (it will automatically detect it)

name=Coinjoiner&network=main&coordinatorUri=https://api.coinjoiner.com/&readMore=https://coinjoiner.com/&absoluteMinInputCount=8

Or you can manually connect by going to Coordinator Settings and pasting to Coordinator URI

https://api.coinjoiner.com/

You should also change the Min Input Count to 8, and then restart Wasabi.

The problem

Privacy has always been a major problem in Bitcoin. Since its inception, many ideas have been proposed; from centralized mixers to various coinjoin techniques. Very few have survived. Governments have been extremely hostile not only to mixing services (labeling them as "money laundering tools") but even to developers who simply write privacy code. This hostile environment has scared away most contributors, pushing privacy-seeking users toward privacy-oriented altcoins like Monero.

Today, the only practical on-chain privacy solutions still alive on Bitcoin are WabiSabi coinjoins and JoinMarket. We believe WabiSabi is theoretically superior to JoinMarket in almost every regard. Currently, the only widely used client that implements WabiSabi is Wasabi Wallet (and its forks).

Wasabi's past doesn't have to be Bitcoin privacy's future

Wasabi Wallet has suffered reputational damage over the years due to several controversial decisions by its original company (zkSNACKs), including:

• Hiring blockchain surveillance firms and blacklisting certain UTXOs based on their analysis [1]
• Several client-side vulnerabilities that could have undermined user privacy [2]

However, Wasabi Wallet is fully open-source and continued working perfectly even after zkSNACKs shut down their coordinator. Since then, independent coordinators have emerged (see: liquisabi.com), proving the protocol itself is sound and can survive State-level attacks.

Where we want to take Bitcoin privacy

We see significant room for improvement, especially in these areas:

• Mitigating potential partitioning attacks that can be initiated by the coordinator (such as using blinding key, round ID etc.) Only then can we truly say that WabiSabi is trustless.
• Improvement of minor but important UI caveats, such as paying-to-many feature and discovering coordinators via nostr without having to rely exclusively on any third parties such as liquisabi.
• Development of a light client that is resistant to supply-chain attacks.

How Coinjoiner works and funds development

Coinjoiner is a WabiSabi coordinator that uses leftover dust from coinjoins to fund the development of the improvements listed above.

It is the most cost-efficient way for privacy seekers to make their coins private while directly contributing to the long-term health of Bitcoin privacy tools.

We want to be completely transparent: there is no "coordinator fee". The revenue comes from rare leftover change that might occur in some coinjoins. As per Wasabi Wallet's own documentation:

In rare cases the output decomposition contains change 
(maximum of 10 000 sats per coinjoin), this leftover goes 
to the coordinator. This is because creating such small 
amounts would harm privacy and ends up being more expensive 
than just forfeiting it.

Bitcoin deserves better privacy

We believe Bitcoin deserves robust privacy solutions that no single entity can shut down.

Coinjoiner is our contribution to that future.

[1] https://bitcointalk.org/index.php?topic=5405325.0
[2] https://github.com/GingerPrivacy/GingerWallet/discussions/116