Vitalik Buterin Proposes Minimal Mixer to Make ETH Transactions More Private

Ethereum blockchain founder Vitalik Buterin is making a call for more privacy in ethereum transactions through the use of a “minimal mixer design” that can obscure user addresses when sending fixed quantities of ether.

Currently there are large privacy problems in the ethereum ecosystem,” Buterin says in a HackMD post. “The default behavior is to do everything through a single account, which allows all of a user’s activities to be publicly linked to each other.

It seems like this can be improved by using multiple addresses, but not really: the transactions you make to send ETH to those addresses themselves reveal the link between them.

Instead, Buterin recommends creating two smart contracts on ethereum: one would be the mixer while other would be the relay registry. This would allow users to make private transactions on the blockchain network through an anonymity set.

Anonymity set is cryptography speak for ‘set of users that this thing could have come from,’” explains Buterin to Coindesk. “For example if I sent you 1 ETH and you can’t tell who exactly it was from but you can tell that it came from (myself, Alice, Bob, or Charlie), then the anonymity set has size 4. The bigger the anonymity set the more privacy you have.

Easy to implement

One appealing point about Buterin’s proposal is that it doesn’t require any protocol-level changes to ethereum. In fact, he notes that a group of users can start implementing it today.

The design’s ease of integration with the current ethereum blockchain is something that Eric Conner, product researcher at blockchain startup Gnosis, believes is its key strength.

Strengths are it gives us a solid privacy solution if users want it,” Conner explains. “The goal is to make a solution that can be easily integrated into current wallets.

Buterin does note that his proposal is a “gas cost,” a fee that those who want to use it for private transactions have to pay. The ethereum founder believes, however, that for the use cases he has in mind for the design, the fee won’t dissuade users.

The main use case I’m thinking of is a one-off send from one account to another account so you can use applications without linking that account to the one that has all your tokens in it,” he tweeted. “So even though it is a 2m gas cost, it only needs to be paid once per account, not too bad.