The system, dubbed “Quorum,” is designed to toe the line between private and public in the realm of shuffling derivatives and payments. The idea is to satisfy regulators who need seamless access to financial goings-on, while protecting the privacy of parties that don’t wish to reveal their identities nor the details of their transactions to the general public.

Amber Baldet, blockchain lead for J.P. Morgan (JPM), introduced the project in a technical steering committee meeting of the Hyperledger Project, a year-old off-shoot of the Linux Foundation that collaboratively researches blockchain tech, at the end of last month. She said the team had chosen to work with Ethereum, despite recent challenges, likely alluding to a recent hacking incident, because it has been around a while and banks are familiar with it. (You can read Fortune’s recent feature on Ethereum-creator Vitalik Buterin in the “40 Under 40” issue of the magazine.)

Unlike the open free-for-all that is Bitcoin, in which anyone with a computer can participate in the network, the nodes that run Quorum must receive permission from some higher authority to join. In many bankers’ view, this gateway prevents corrupt or malicious operators from entering the system. Critics, meanwhile, counter that requiring permission bucks the main benefit of a blockchain: enabling untrusted parties to interact.

In practice, J.P. Morgan’s Quorum is a modification of the Go Ethereum client, a popular software program that supports the Ethereum network. Quorum features an updated consensus mechanism, the process by which different computers agree on the order and legitimacy of transactions on the network, created by Jeffrey Wilcke, one of the founders of Ethereum and developer of the Go client.

In effect, Quorum has two layers of consensus on a single blockchain, meaning two ways of reaching agreement about its transaction records, both stored on one distributed database, or blockchain. The first layer verifies public data, and the second layer verifies private details.

“We get the best of both worlds,” said David Voell, engineering lead for J.P. Morgan’s corporate and investment banking group, during the Hyperledger presentation. The technology swaps out private transaction data for cryptographic hashes, condensed and scrambled versions of that data, which conceals their true contents. Both the public and private data reside on the blockchain, but they’re parsed separately, he said.

“The key to this whole thing, again, is a single blockchain of everyone continuously checking the integrity,” Voell said. And yet there is still a “clear separation between private and public,” he added.

The slideshow, available online on Google Drive, presented the system as “a permissioned implementation of Ethereum supporting data privacy.” (An audio recording of the presentation is available here.)

The banking sector has been touting blockchain tech as a possible way to cut costs and revamp back-office IT functions.

Get Data Sheet, Fortune’s technology newsletter.

J.P. Morgan has also worked on a project called Juno, another distributed ledger that emphasizes scalability in its design. At the same time, a number of companies are building private blockchains, including R3, Chain, and Digital Asset Holdings.

“We have people building the most stress-tested financial systems in the world,” Baldet told the Wall Street Journal. “Bringing that enterprise expertise [to blockchain] is one of our strengths.”

The J.P. Morgan representatives on the call said they plan to open source the documentation and code base behind Quorum by the end of the year.