ZeroLink is a 2017 fungibility framework from Adam Ficsor (nopara73) that turned a loose set of privacy ideas into a concrete wallet architecture. Instead of treating CoinJoin as a single transaction trick, ZeroLink defines the full operational flow: coordinator interaction, credential handling, fee logic, output registration, and post-mix wallet behavior.
That broader scope is why ZeroLink still matters. It gave developers a structured way to build privacy wallets that were usable by normal people, not just protocol specialists, and it directly influenced early HiddenWallet and Wasabi design choices.
ZeroLink Pillars
At a high level, ZeroLink is built on three practical principles that work together. If one part is missing, the privacy benefit drops quickly in real-world usage.
- CoinJoin coordination: Users register inputs with a coordinator, obtain blind-signed credentials, and redeem them for anonymized outputs.
- Wallet hygiene: Mandatory fresh addresses, randomized fees, and separate change outputs.
- Toxic change policy: Wallets automatically quarantine change and avoid merging it back into mixed UTXOs.
From ZeroLink to Wasabi
Wasabi Wallet became the first widely known implementation path in 2018. In 2021, the team moved to WabiSabi, which replaced simpler credential mechanics with KVAC-based logic that supports more flexible denominations. That change improved usability and pool composition while keeping the same core goal: break deterministic links without exposing users to custodial risk.
Independent analysis, including work such as Stutz et al. (2021), helped test how these designs behave under real transaction conditions rather than ideal protocol assumptions.
Why ZeroLink Still Matters
ZeroLink remains a baseline checklist for evaluating collaborative Bitcoin privacy tools. When a wallet claims stronger privacy, the practical questions still come from this framework: how are credentials blinded, how is change isolated, what metadata is retained, and where can user behavior accidentally collapse anonymity sets?
Even where implementations differ, the ZeroLink model continues to shape how developers reason about coordinator trust, wallet defaults, and user safety. It is less a historical artifact and more a reference architecture that keeps showing up in newer protocol and wallet work.
References
- ZeroLink specification (2017)
- WabiSabi white paper (2021)
- Adoption and Actual Privacy of CoinJoin Implementations (2021)
ZeroLink is a privacy framework, not a legal shield. Use CoinJoin tooling lawfully and follow the regulations that apply in your jurisdiction.
Author
NotATether
Bitcoin privacy researcher and maintainer of BitMixList. Focused on mixer history, enforcement timelines, and practical privacy workflows for users operating in high-friction jurisdictions.
