A new BTCPay Server plugin developed by BTCPay Server contributor, Andrew Camilleri, based on Wasabi Wallet’s WabiSabi coinjoin coordination protocol introduces bitcoin privacy to BTCPay Server merchants with just two clicks.
Merchants can now reclaim their privacy while managing their BTCPay Server stores the same way they did before. Any BTCPay Server merchant can activate the optional coinjoin plugin instantly for their stores. BTCPay Server stores that activate the coinjoin plugin will be able to automatically coinjoin all the bitcoin they receive. This protects the privacy of all their incoming and outgoing transactions by preventing sensitive information about their store’s payment history from leaking to unconcerned parties.
In addition to auto-coinjoin, the BTCPay Server plugin also offers an unprecedented payment batching in coinjoin feature. Utilizing BTCPay Server’s scheduled payouts, users are able to pay addresses directly within a coinjoin transaction, which saves block space and provides greater privacy compared to making a payment in two steps.
Also included is a detailed coin selection interface allowing merchants to spend their coins based on their gained anonymity scores. In addition to the default zkSNACKs coordinator server, merchants are able to discover alternative coinjoin coordination servers via the Nostr protocol and can easily run their own coinjoin coordination servers. Adding coinjoin in a BTCPay Server store only requires users to activate the option in plug-in settings and restart the server for new settings to apply.
By using Wasabi Wallet’s WabiSabi coinjoin coordination protocol, merchants can perform arbitrary amount coinjoins rather than fixed denomination coinjoins as required by other protocols. This greatly reduces the amount of non-private change users receive and also makes payments inside the coinjoin possible.
Protecting Customer Information, Company Funds, and Employee Salaries
Even with sovereign payment processing platforms such as BTCPay Server, privacy is hard to protect on Bitcoin. A BTCPay Server merchant earning bitcoin for their products and services should not have their transactions tracked. And yet today, merchants from all around the world unwillingly, and sometimes unknowingly, leak personal and commercial information via their bitcoin transactions. Up until now, merchants living on a bitcoin standard have had most of their business activities monitored by many parties such as clients, suppliers, or employees. This is a known issue inherent in the open design of the Bitcoin network and requires new technology to be mitigated.
When a merchant consolidates bitcoin UTXOs from their store to optimize for network fees, all the wallet history gets leaked on the blockchain, allowing anyone who transacted with them to learn about payments made by other customers. The store’s transaction volume, total available balance, and customer base can be unwillingly leaked. This is unacceptable and is not something that merchants should be concerned about. Unfortunately, UTXO consolidation at the cost of privacy remains a common practice for many merchants processing high volumes of transactions. A merchant has only so many things they can focus on to deliver great products and services to their clients, and a lack of financial privacy should not be one of them.
“BTCPay Server is the most sophisticated merchant payment processing software for bitcoin. It only made sense that it would include an optional coinjoin plugin with the most sophisticated privacy-enhancing tool for Bitcoin. As a coinjoin protocol, WabiSabi has been designed with merchants in mind, enabling payments inside coinjoin and optimizing block space usage to save on fees.” - Max Hillebrand, Wasabi Wallet Contributor & CEO at zkSNACKs
BTCPay Server merchants can access a comprehensive dashboard to assess the level of privacy of their wallets, the details on the current coinjoin transaction they are participating in, and gain additional insights and control with coin selection in and out of coinjoin transactions.
Enabling New Coinjoin Coordinators
All BTCPay Server merchants can now benefit from powerful privacy tools straight from their store. BTCPay merchants can choose to coinjoin for a fee with a highly liquid coordinator provided by zkSNACKs, the company behind the privacy wallet, Wasabi Wallet. On top of that, all BTCPay Server admins can spin up their own coinjoin coordinators using their own terms, built upon Wasabi Wallet’s robust WabiSabi coinjoin protocol. They can then advertise this coordinator via the Nostr protocol. This can create a new free market of coinjoin coordinators with different policies and fees, opening up a wide array of choices for all merchants.
If users choose to run their own coordinator, the BTCPay Server Plugin offers an optional revenue sharing feature that by default donates a percentage of proceeds to the HRF and OpenSats foundation to further Bitcoin development. In addition, the plugin allows users to participate in different coinjoin rounds across multiple coordinators at the same time.
"BTCPay Server was created to empower individuals and businesses to regain their financial sovereignty. The Wasabi Wallet team and I are proud to offer even more privacy protection with this new coinjoin feature. I believe that financial privacy is a fundamental human right, this feature is my contribution to that cause.” ~ Kukks, Contributor at BTCPayServer and developer of the BTCPay Coinjoin Plugin.
For any questions about the BTCPay Coinjoin plugin, please contact https://chat.btcpayserver.org
About BTCPay Server
BTCPay Server is an open-source bitcoin payment processor that is censorship-resistant, free to use and self-hosted, which drastically improves payment processing for global merchants in all parts of the world. Features already include automatically generating unique addresses for each new payment, custom address labeling, invoicing, and advanced wallet management options such as coin control. More information here.
WabiSabi is an anonymous credential scheme for centrally coordinated coinjoin transactions. It utilizes keyed-verification anonymous credentials, homomorphic value commitments, and zero knowledge proofs to achieve privacy and flexibility. WabiSabi allows users to utilize arbitrary amount coinjoins rather than fixed denomination coinjoins and reduces the amount of non-private change produced in other coinjoin transactions. More information here.
About Wasabi Wallet
Reclaim your privacy with Wasabi Wallet, a free and open source bitcoin wallet with built-in coinjoins. Coinjoins are collaborative bitcoin transactions to enable cash-like privacy features for bitcoin. More information here.