ZeroLink: Massive Scale CoinJoin Is About To Be Deployed - Participate In The Final Test And Earn $10

Update: The testing is over. Click here to see the results.

A while ago I decided to improve privacy and fungibility in Bitcoin. I created a Bitcoin wallet, called it HiddenWallet, that protects its users from network analysis. I worked on TumbleBit, a Bitcoin mixer, that protects its users from blockchain analysis.
While integrating this technology into HiddenWallet, I recognized with CoinJoin we may be able to achieve the same trustless tumbling, but faster and cheaper. So I dropped my half ready integration and came up with Chaumian CoinJoin. However, coin mixing does not automatically provide untraceability. Even if network level tracks are completely eliminated, examining transaction chains and other transaction metadata, attackers may still be able to recognize some patterns. So I created ZeroLink to systematically tackle these potential information leaks. ZeroLink is an end-to-end privacy solution. Nothing is out of its scope. Thus, ZeroLink will enable the fully anonymous usage of Bitcoin, for the first time.

We need you!

During the past months, with Matthew Haywood, we successfully built a prototype, integrated it into HiddenWallet and we are preparing for our final test on the Bitcoin test network, where we would like you to take part.
Anonymity likes company, you cannot be anonymous by yourself. On the Internet, you must hide in a crowd. Consequently, we are not comfortable releasing our software on Bitcoin, if we cannot achieve sufficient anonymity set on the Bitcoin test network first, with real people.

Passive participation. We have to coordinate the test to happen in a specific time. However, you do not have to be present, you can start tumbling right now and let it run, wait for your peers to join to the mix. The mixing round will kick off, if either of these conditions are fulfilled:

  • 100 users joined to the mix.
  • Dec. 20 (Wednesday), 10 PM London time passed AND at least 21 users joined to the mix.

Convenience note: Dec. 20 (Wednesday), 10 PM London is 5 PM in New York, 2 PM in San Francisco and Dec. 21 (Thursday) 6 AM in Taipei.

Click here for step by step guide to participation…

Success Criteria For Mainnet Release

If at least one CoinJoin transaction is published to the Bitcoin test network with at least 100 anonymity set, we will release it on the main network.
If the test fails, or under 21 users start tumbling, therefore the CoinJoin will not happen, because the minimum anonymity set is not hit, we will not release it on the mainnet.

If the anonymity set is between 21 and 100, we will reconsider releasing it on the mainnet.

Why release an unstable version on the mainnet?

Unstable does not mean every part of the code is unstable. There are robust parts, too. For example, nor coin or privacy loss due to software error will happen. These parts are well tested. For example, in case of mixing, the software will not sign the CoinJoin transaction, if it does not see its desired output between the outputs of the CoinJoin. This process is risk free.

Furthermore, anonymous Bitcoin is too important to sit on it for years.

Claiming Participation For $10

Note. I will not touch the donations I got so far, I am not sure every one of my donors would agree, this is the best way to spend it on. Yet, as you may have noticed, I am fully invested emotionally in this project, therefore I will pay you guys out from my own pocket. However, unlike many of you, I am not a Bitcoin millionaire, I spent most of my time contributing to open source projects, which do not pay. Thus, I would like to kindly ask you, if $10 is nothing for you, consider not claiming it.

Process of claiming the $10. After the mix, you send me an email to This email must contain your Bitcoin address and a transaction hex.
Obtain this transaction hex from HiddenWallet by building a transaction with a mixed coin and clicking on “Copy Transaction Hex” button. However, do not broadcast it to the network, instead cancel it out. If you would broadcast it, then anyone would be able to claim your money from me.

Of course this also means, if I miscalculated something and the test is not successful, I am not able to verify you indeed took part in the mix.


If you are thinking about contributing to the project, but cannot decide between joining the mix and sending a pizza, please consider choosing the former one..