Why We Need On-Chain Privacy

Original author: Matthias Heinrich Morales

Original compilation: 0x21, Rhythm BlockBeats

Openness and transparency on the chain is a double-edged sword for all users. Your resume and NFT collection, on the other hand, your every move may be monitored by others, completely losing your personal privacy.

zkRollups can use zero-knowledge proof technology to integrate privacy into the Rollup scheme, but at present, most zkRollups schemes have little effect on the privacy of zero-knowledge proof Not much involved.

The author of this article, Matthias Heinrich Morales, explained the feasibility of privacy protection based on the zkRollups scheme. He believes that transactions on the chain should be anonymous by default. to protect personal privacy. In the case of complete anonymity, users can choose whether to disclose some personal transactions to the chain based on the programmable privacy protection mode. Rhythm translates the original text as follows.

In this article, the privacy-based protection I mentioned is based on the zkRollups scheme, why do we need privacy protection so much. How do zkSync, Starknet, and Aztec compare and what are the differences?

Privacy protection is the key factor for the success of most of the current encryption field and zkRollups. In the following elaboration, I will mainly introduce the following points:

Why Privacy Matters

Why it should be our default option

Why zkRollups can be a unique catalyst

How to compare some mainstream projects in the zkRollups solution?

Why privacy is so important

Web3.0 is a new paradigm that allows users to control their own personal data and decide whether to share it or not. (No transaction or transfer will be initiated without a message signature) However, we are in the Web 3.0 era on Ethereum, which has no privacy by default because all transactions are public Name, once someone knows your wallet address, then they can still track everything you do on the chain, and everything that intersects with you.

On the one hand, this is a good thing, imagine if your wallet address can link your ENS domain name, and show others the NFT collection on your chain, That's what a lot of people hope to get out of it. In other cases, such as you transfer a large amount of funds through certain DeFi projects, I believe you are unwilling to make this information public.

zkSync got it right in their user manual: "Some residents living in impoverished or dangerous areas may not expenses, because these merchants can easily know how much money they have in their hands.”

To circumvent this, many users have both public and private addresses, WPMonty (technical member of Bankless Dao) once wrote an excellent article 《3 Rules for Healthy Pseudonymous Hygiene with Ethereum" to introduce how to keep two addresses independent of each other.

However, for many new users, setting up multiple addresses and maintaining them properly is a waste of time and money without a simpler and more abstract solution. If this cannot be done, how can we believe that future cryptocurrencies can become mainstream? From this point of view alone, we can see the value of private transfers.

Why Privacy Should Be Our Default Option

In fact, there are currently several solutions to this problem, and it is optional to protect privacy on Ethereum, the most eye-catching one is Tornado.Cash (Tornado protocol). However, these optional privacy protection schemes are accompanied by many limitations.

For example, through Tornado.Cash users can only transfer a fixed amount of ETH, not an arbitrary amount, although the latest version of Tornado Nova is already in the experiment, but Still largely hampers the practicability of these protocols.

Even if the practicability of this aspect is not an urgent problem to be solved, the amount options for private transfers are limited, but at present, this default global anonymous method is only Can be considered the highest level of privacy protection.

In other words, by default, if private transactions allow us to go from simple global privacy protection to programmable private transactions, then the Bringing privacy-related Dapps into a whole new world.

Why zkRollups

In fact, programmable privacy transactions have been implemented on other chains, such as SecretNetwork, and can also be applied to the Ethereum chain in a cross-chain manner. However, cross-chain has caused a series of new security issues, such as the recent WormHole incident and cross-chain bridge vulnerability incident. Hacker attacks remind people that this technology must be more mature.

In fact, based on cross-chain solutions, Vitalik once said that the future will be a "multi-chain" era rather than "cross-chain".

Therefore, it is better for the privacy solution to run directly on Ethereum, so that Rollups will also inherit all the security guarantees of Ethereum (through the L1 smart contract operation) and can also reduce costs incurred during the transfer process.

The zkRollups scheme is particularly suitable as a default privacy setting, first of all, it reduces marginal costs as it scales down. Second, it has broad verifiability. Finally, the zero-knowledge proof technique used by itself is also commonly used to protect privacy. Just like TornadoCash still needs to rely on zkSNARKs to apply zero-knowledge proofs on L1.

If you don't know zkRollups yet, then this professional article written by CryptoCanti may be able to help you very well 《Ethereum-powered ZK-Rollups: World Beaters》

How do some mainstream projects in the zkRollups program compare?

Let's take a look at the comparison of zkSync, StarkNet and Aztec based on the zkRollups scheme on the Ethereum mainnet in the state of default privacy protection.

zkSync

zkSync was founded by @gluk64 and @Shamatar and developed by Matter Labs Scalable payment scheme. zkSync aspires to bring cryptocurrency to the masses, with strong philosophical safeguards and liberal economic development measures around the world.

zkSync plans to use privacy-by-default as part of its development, and over time will apply private transfers to programmable privacy Dapps. But so far, zkSync has no privacy protection function available, and users still need to rely on third-party protocols for private transactions.

zkSync also stated on Twitter that "when the "proving party technology" does not require high costs and has elastic consumption, privacy functions will be added and put on the platform."

This kind of transfer to the default privacy setting must be a smart contract with full privacy protection, just like the zkSync team said: "The privacy protection mode must support programmable, Because the application cases in real situations are not just as simple as transferring money.”

The result of changing the current transaction mode to the default privacy mode is unknown, but we may be able to look forward to the changes brought about by the launch of zkSync2.0, and then Let's introduce its actual application zkPorter.

StarkNet

StarkNet was developed by @EliBenSasson, @ukolodny, @RiabzevMichael and @Alessandro Chiesa Co-founded, the composable zkRollup network launched by the StarkWare team. They focus on the development and research of zero-knowledge technology to improve the scalability of blockchain.

Before StarkNet, they had developed StarkEx's zkRollup solution, which provided specific applications or teams such as dYdX, ImmutableX and Sorare through general smart contracts help.

The team behind StarkNet is still targeting the L2 Rollup scheme instead of the default privacy scheme, however they still embrace the team that can bring the privacy scheme to StarkNet .

StarkNet also clearly stated on the official website, "Any team can deploy various privacy protocols on StarkNet, and all network participants will provide complete privacy support. And be able to solve the massive computational pressure required in the privacy protocol through the scalability of StarkNet.”

From StarkNet's popular project construction directory, it seems that there is no agreement to provide privacy transactions in Rollups, maybe it will be StarkNet mentioned that it is One of the 80 secret agreements of the building.

Over time, we can also expect StarkNet's own privacy protocol for the Rollup scheme, in the form of L3 or L4 to support running on L2 (non-private) .

For StarkWare content, please refer to this article《Fractal Scaling: From L2 to L3》

So far, there is no conclusion on whether StarkNet will launch privacy transactions and programmable privacy transactions.

Aztec

Aztec is led by @Zac_Aztec, @jaosef and @rel_Aztec, The privacy-first philosophy extends deeply to the study of default privacy forms and programmable privacy settings.

The whole team is deeply involved in basic research. For example, they published the original PLONK paper, which established a theoretical foundation for many teams.

By default, all private transactions in Aztec’s Rollups solution are completed using the shielding mechanism, but many applications and programs are currently restricted. The protocol currently only supports private transfers through zk.money.

Soon zk.money will open to allow private accounts to inject liquidity in L1, interact with DeFi protocols, and use the company's SDK to realize reuse functions.

Using the Aztec contract SDK is a very novel solution, which protects ETH by protecting the interaction between L2 and L1 smart contracts and sending them back to L2 privacy.

The beauty of this approach is that it allows fully private smart contract interactions without requiring the DAPP to be deployed on Aztec's L2 (and has a fully equivalent ZKEVM with EVM)

Aztec Connect is currently live on testnet and will launch on mainnet on March 22nd.

Over time, Aztec hopes to bring fully private programmable solutions to L2 through its proprietary smart contract language Noir. Noir is a fully open-source, high-level rust-like programming language, which is a zero-knowledge technique for compiling the PLONK backend software. The project is also currently hiring a language architect.

Summary

We can see that Ethereum needs privacy, and the default privacy will be the most secure. The top priority of the zkRollup solution is to provide complete privacy and programmability, and the above three teams of zkRollups in the Ethereum solution are also working hard to improve the functions in all aspects.  

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