Builder: Yuval Kogman (Nothingmuch)
Language (s): rust, c#, go, python
Contribution (S/ED) to: Rust-PayJoin, Wabisabi/Wasabi 2.0, General Privacy Research
Work (S/ED) at: Spiral (currently), ZKSnacks (formerly)
Yuval had an interest in topics related to Bitcoin far before it was actually born in the world. A life -time software developer and technology enthusiast, as well as a general autistic, he first became interested in cryptographic technology around 2002.
His father participated in a speech by Adi Shamir, the famous cryptographer, who invited the RSA signature scheme at Ecash. A father-son conversation later, and Yuval was now aware of linkable ring signatures, the double consumption problem and the concept of Ecash. His journey down the rabbit hole had begun before the Bitcoin branch had even removed a single bucket of dirt. He even ran hashcash on his mail server in the early 2000s.
Like many bitcoiners at the time (including myself), Yuval saw the original Bitcoin article about Slashdot in 2010 and immediately rejected the whole idea as silly and incapacitated. Later in 2013, he realized that Bitcoin was still around, chugging with and produced a block about every ten minutes, but still Yuval was not to get more involved.
Eventually in 2015, he took advantage of an offer that someone did to sell him some, and so did the trick. In fact, owning some Bitcoin himself was the last push he needed to really go down the rabbit.
Aim through the noise
Throughout the beginning of its time in this room, Yuval focused very strongly on examining different privacy coins.
When asked what made privacy to such an important focus area for him, he said this: “Realizing my silly impulse purchase or poor choice of wallet software was recorded on chain for everyone to see, and possibly made me an easy target if Bitcoin would be banned one day.”
Despite all the different approaches and potential progress with privacy coins at the time, nothing fully convinced him that they were a solution despite all the progress they had made in different fields.
“Even when I realized that I only really believe in Bitcoin, Impostor Syndrome kept me trying to learn about all the things. At that time, the speed in which new things to understand consisted were size orders more than I could follow, but it took me a while to stop trying,” he said of that time period.
For a while he simply fooled on Reddit and Bitcoin Twitter, softening in what was going on, but not really participating to any extent in addition to examining and learning. The first community he actively participated in was an open voice chatterer called The Dragon’s the one he heard about on Bitcoin Podcast Block Digest (Disclosure: The author served both the chat server and hosted the podcast in question).
Wabisabi and Wasabi 2.0
Yuval was one of the designers of the Wabisabi protocol implemented in Wasabi Wallet 2.0. Wabisabi was a protocol designed to facilitate coinjoins of flexible church communities as opposed to any output that should be exactly the same amount. He was quick to point out that it was simply to combine an aspect of confidential transactions with anonymous credentials, something Jonas Nick highlighted was the prototype already into an ECASH implementation.
One important thing to make it clear is that Wabisabi is simply the mechanism that replaces blind signatures for users to interact with the coordinator and perform the build-up of a coinjoin transaction, it is not part of how these coinjoin transactions are structured or look at the chain. However, it was specifically designed to allow coinjoin Transactions to be structured with arbitrary amounts without being a point in failure that could deanmate users trying to create such transactions for the coordination server.
While the Wasabi 2.0 implemented the Wabisabi protocol itself, the ZKSnacks team ignored almost the entire research and the work Yuval did on the structure of arbitrary amounts Coinjoinoin transactions. He performed this work to ensure that the transactions Wabisabi coordinated were sufficiently private and did not implement behavior or transaction structures that could undo users’ privacy after the fact.
“Where things went wrong is death by a thousand cuts, with the primary reason for being that Nopara73 and Molnard refused to learn something about how to avoid the same mistakes already made in Wasabi [1.0.]”
As he expanded it, he said, “Everything from the choice of coin, to when the decisions about what output values they should use, when coin joins are done, to how tor is used if corners were cut and implemented based on vibes without understanding the underlying mathematics. Even the game theory assumptions needed to deny the service concept to really work.
As a specific example of general incompetence, he witnessed in ZKSnacks that he said this, “a related ‘fun’ fact, although ZKSnacks for years claimed they did not hold any logs, the unnecessary use of mostly standard configuration NGINX to operate the site by means of the same host. cooled. “
In the end, he left ZKSnacks because of his rejection of the corners, which the company cuts and his unwillingness to participate in it.
Yuval’s current opinion on Wasabi -Tevebog, especially considering the current environment for more people running Wasabi 2.0 coordinators, is that no one should use a coordinator server unless they trust that the server does not benefit from implementation and protocol voys to dancing them.
The state of things
“Privacy is a human right, but in Bitcoin it is also a personal security question for more or less someone on a long enough time horizon.”
Yuval’s view of the current state of Bitcoin privacy life is not the rosiest. He has a number of concerns with the general landscape as it stands now. Especially detention exchanges are exaggerated in their rejection of interacting with users using privacy. He sees nothing about the use of privacy tools that prevent you from selectively passing on information to an exchange when needed.
“There is a difference between sharing your information with exchanges you trust and by extension of regulators and broadcast it for the whole world to see,” he said.
Apathy from users is another thing that concerns him. Many users don’t care about their privacy if they even consider it, and the use of privacy among Bitcoin users is realistic a very small thing. In some social circles, there is even a stigma about privacy. “… Apathy associates this stigma, which effectively normalizes the absence of privacy[.] Exchange does not lose many customers if they refuse to serve customers who use privacy technology, ”he said.
He is also not very pleased with the current state of privacy.
“[R]ENT -SEKS “Privacy Wallets” Snake Oil Peddlers has poisoned the well. Their zero-sum brainworm attacks led them to spend their time slinging in Twitter-feuds instead of God forbidden to open a textbook or academic paper. This toxic discourse also alienated users and fed into apathy and stigma. “
Ultimately, all these concerns are anchored in social issues, how people or businesses act, how people respond to other actions, etc. This is how they should ultimately be resolved.
“Without adequate user approach for privacy and to normalization of its use, Bitcoin is a hell of a monitoring tool.”
Spiral -shaped
In September 2023, Yuval was hired full -time by spiral to work full -time at Bitcoin Privacy Research and Development. Given that many of the problems of current coin -join implementations stem from their dependence on a centralized coordinator server, Yuval has decided to focus his work on decentralized coinjoins.
As such, he works at Spiral to decentralize coinjoin coordination and improve the ability to analyze and optimize multiparty transaction structures for privacy.
“My long -term goals are to look through my now more developed ideas for coinjoin. Privacy must have close to 0 marginal costs, or high fees will deter its use. It should also not be a” product “that grifters can shill to get a quick buck by deceiving uninformed users.
[An intersection attack is an attack taking advantage of mixed coins being spent in the same transaction(s) together improperly to deanonymize their history.]
He is currently contributing to the Rust-Payjoin Library maintained by Dan Gould to work towards his final goal of a decentral coin join protocol.
“Payjoin is currently [specified] As a 2 -party cooperation transaction construction protocol. Although this only achieves the first of these two goals, it allows to generalize it to several parties the opportunity to make the third correct, potentially in any wallet. “
Covenants
Yuval believes that covenants are a valuable improvement of the Bitcoin protocol, but believes that the current set of covenant proposals is made to be more effective in the long term than they would actually be alone.
“The current favorites, CTV+CSFs, seem like a significant step forward, but the way I see would not be sufficient for the kind of long -term scaling improvements we need for global adoption, even though CTV is generalized to txhash.”
He is a fan of the Varops concept from Rusty Russel’s large script -restoration proposal as a general mechanism to limit more complicated covenants or other opcod to prevent them from making block validation for expensive for users.
“I am sorry to say that I also find that many of the discussions are disappointing tribe, with many words spent on cranging in circles about why one’s favorite opcode is the best hammer, because see how many problems that look like a certain kind of nail if you mint hard enough and you are such an idiot and on top of the clearly dishonest not to share my preferences.”
In general, he believes that the conversation about covenants is poorly controlled, with too much focus given to individual covenant proposals rather than considering what kind of use cases we want to activate and what uses we do not want to activate, and work backwards from there to design appropriate suggestions to service the desired use cases.
Use it or loss it
As for what average bitcoiners can do to improve their own privacy or support privacy in general, he had this to say:
“Accept that there is no magic solution, we are a little stuck with the bitcoin we have gotten as far as the transaction graph. Then critically assesses what solutions are available, affordable and safe to use and use them.”
In the end, privacy requires everyone to intervene. So what do people do? Lyn offers an improved degree of privacy, there is still a joinmarket and wasabi (with disclaimers from above). Do what you can. Examine the tools, check what you can, and make sure you are considering who you are trying to stay private and how much effort it will take to do so.
“Even if you don’t think you need privacy today, at least find out what you could afford to use if you may need it tomorrow so you won’t be caught up with guard. Also consider that the people who really need it today do not have it without those who can live without it, so if you want that opportunity tomorrow, exercise it or loss it.”