Like Bitcoin, Ethereum has become public infrastructure. And like the genesis blockchain, Ethereum doesn’t have privacy measures baked into its first layer.
But if Ethereum is to become a better and more universally practical public blockchain, it will need improved privacy so that users — individuals, enterprises, DAOs, what have you — can leverage its public chain while remaining anonymous, as if they were using cash.
That reality has led to recent calls in the Ethereum community for the creation of a reliable mixer, one that could be used to obscure transactions’ participants in trustless fashion.
Now, thanks to the efforts of one “genius” developer, a promising stab at such a mixer has arrived in Heiswap.
There’s a New Mixer in Town
Built by Kendrick Tan, Heiswap — hosted at heiswap.exchange — is an Ethereum mixer that obfuscates the origins and recipients of ether (ETH) in mixing fixed sums of the cryptocurrency, its blockchain’s figurative fuel.
Tan’s work builds off the minimal design specification Ethereum co-creator Vitalik Buterin published back in May, the spec being a near-immediate response to Ethereum community member Eric Conner’s call for a “basic mixing service.”
— Eric Conner (@econoar) May 22, 2019
At the time, Buterin outlined a “simple mixer for sending fixed quantities of ETH.”
As such, Tan built Heiswap from that outline and has since released the mixer on Ethereum’s Ropsten testnet. Upon publishing the dapp, Tan was hailed as one of the “[r]andom geniuses” currently working around Ethereum by Buterin.
This is one of my favorite things about the ethereum community. Random geniuses I've never heard of coming our from faraway lands with cool projects like this. https://t.co/VpIgkZcBnE
— Vitalik Non-giver of Ether (@VitalikButerin) July 4, 2019
How Does Heiswap Work?
The mixer uses a smart contract, into which users can submit fixed amounts of ether — e.g. 0.1 ETH, 10 ETH, etc. — that is afterward matched with another user’s similarly denominated sum in order to hide a transaction’s true source.
As Tan explained of the project:
“Heiswap (黑 swap) is an Ethereum mixer that allows users to ‘wash’ their ETH in a confidential manner (i.e. who the sender sends money to is hidden). At this point in time (3rd July 2019), Heiswap is only able to mask the link between senders and their corresponding recipients, and requires participants to send ETH in fixed denominations.”
Similarly to Monero (XMR), Heiswap’s privacy scheme utilizes so-called ring signatures, Tan added:
“Heiswap ulitlizes Linkable Ring Signatures in conjunction with (pseudo) Stealth Address to achieve zero-knowledge mixing.
The signatures are verified on the smart contract end, while the signatures are generated on the frontend. That way, you don’t need to submit your private key to the smart contract ;).”
Of course, it must be noted that Heiswap has yet to be audited, as Tan said he didn’t have the necessary funds to enlist an audit by himself.
An interesting possibility on the auditing front could come from MolochDAO, an open-source group of Ethereum stakeholders that are crowdfunding Ethereum development projects.
Ameen Soleimani, the chief executive officer of SpankChain and the founder of MolochDAO, had previously floated the idea of paying for someone via a Moloch grant to develop a mixer from the minimal design spec Buterin had provided.
We need a privacy champion!
Please RT! https://t.co/iMGnZAdk9g
— Ameen Soleimani 👹 (@ameensol) May 22, 2019
Now that Tan has seemingly provided such a mixer, perhaps Soleimani and his Moloch peers would be willing to shift funds to an audit of Heiswap instead. Of course, that’s a matter for MolochDAO to decide, but it’s a possibility that could conceivably gain consensus going forward.
Notably, Heiswap is underpinned by smart contract tech rather than servers, which can be seized. That dynamic will work in its favor with regard to censorship resistance.
In May, European authorities seized six servers powering the bitcoin mixer service Bestmixer. To be sure, mixer’s aren’t only for criminals, but the aforementioned authorities determined the service had become popular among money launderers.
In contrast, Buterin’s mixer design came in response to Ethereum users wanting to join a DAO, specifically HumanityDAO, without publicizing their main addresses.