Remember when J.P. Morgan's Jamie Dimon warned that Bitcoin could eat the banking industry's lunch? Since then the bank has pivoted to broadly embrace FinTech, placing big bets on machine learning and a new startup residency. Yet nothing has captured the attention of the public quite like the release of Quorum, an open source blockchain platform built on the shoulders of the public Ethereum project. Targeting risk-averse corporates who want to keep their data within walled gardens but with a design that keeps the door open for future integration with the explosion of FinTech innovation currently happening on Wild West style public networks, Quorum might be the missing link that inspires business giants to ask if they can join the cool kids for lunch.

While Bitcoin is best known as an unstoppable, globally distributed payment system, Ethereum is an unstoppable, globally distributed computer. Each network has its own native cryptocurrency: bitcoin and ether, respectively. Ethereum also supports smart contracts which allow the creation, registry, and trading of bespoke digital tokens representing virtual shares, land titles, identities, debt instruments, or almost anything else a person might want to own or share with the world. In both Bitcoin and Ethereum, every transaction is recorded to a shared ledger called the blockchain. Because everyone sees the same ledger without the human-intensive operational processes financial firms use keep today's records in sync, banks and exchanges have been quick to see the potential cost saving opportunities of moving to a blockchain world.

But there's a hitch. On a public blockchain, all activity is visible to the world, while the actors themselves are shielded behind disposable "cryptographic wallets" that effectively render them anonymous. Unmasking user identities would be akin to publishing everyone's monthly bank statement on the internet, but keeping them hidden means it's easy to avoid anti-money laundering and sanctions checks mandated by governments and regulators.

Enter Quorum. The "enterprise blockchain" platform created by J.P. Morgan, but now part of the public domain, allows groups of banks, businesses, or simply individuals to create a private version of the Ethereum network just for themselves. Participants in a Quorum network can transact confidentially so no one can see who is trading what with whom, while still getting the data integrity and information security benefits of a distributed blockchain system.

Quorum initially shipped with two main features. QuorumChain , an alternative to Ethereum's proof-of-work consensus mechanism removed the need for energy intensive "mining" and was built in by Ethereum co-founder Jeff Wilcke. Constellation, Quorum's privacy engine, was developed in-house at J.P. Morgan.

Constellation works by allowing smart contracts to be encrypted and distributed to only those directly involved in a transaction. While a few other "consortium chain" platforms use point-to-point or "off-chain" business logic, the difference in Quorum is that a hash (a "digital fingerprint" in blockchain lingo) of the encrypted smart contract is published to the blockchain shared among everyone, so all can verify the integrity of the whole system without needing to see the inner workings of each sensitive transaction.

Quorum and Constellation's Lead Engineer Patrick Nielsen, said: "The participants in a Quorum network are known by their public keys and any key to which you address a transaction containing a smart contract will have the ability to read and execute it. It's a lot like PGP encrypted email."

It's a deceptively simple and elegant solution Zcash Scientist Eran Tromer called, "probably the best you could do with today's technology."

That's an oddly endearing sentiment, coming from a technologist at one of the most advanced crypto-privacy R&D shops in the world. Zcash is a cryptocurrency for people who think the problem with Bitcoin isn't that it's anonymous, but that it isn't anonymous enough. Unlike Quorum's focus on permissioned networks and well understood public-private key infrastructure, Zcash exists on a public network where privacy solutions rely on mind-melting math and are still academically contentious.

Working at completely opposite ends of the blockchain spectrum, there were more than a few people surprised at the recent announcement of a partnership between J.P. Morgan and Zcash's parent, the Zerocoin Electronic Coin Company, to abstract the state-of-the-art Zero Knowledge Security Layer from Zcash and add it to Quorum.

"The ZSL, which we're calling the Zero Knowledge Settlement Layer when applied to Quorum, augments the existing Constellation engine to allow cryptographically private settlement of digital assets," said Zcash's CEO, Zooko Wilcox.

Amber Baldet, Executive Director and Program Lead for J.P. Morgan's Blockchain Center of Excellence, clarified the nature of the partnership. "J.P. Morgan is not buying or trading Zcash," she said, "We are working closely with the ZECC team to bring the concept of shielded settlement tokens (z-tokens) to Quorum. Z-tokens allow us to store information about who owns what on a secure blockchain shared among all Quorum nodes in a way that prevents double spending and increases the ability for regulators to know they've got complete reports, while the computationally heavy workflows that impact those tokens – trade affirmations, confirmations, interest payments and the like – continue to live off-chain in the relevant Constellation nodes."

At the heart of the design is the conviction that a walled garden doesn't mean cutting corners on security or assuming that because big businesses know each other, they trust each other not to try to cheat.

Supply chain logistics and supply chain financing, for example, are conjoined businesses everyone seems to agree would be better on a blockchain. What might start out a small network between say, Wal-Mart, Alibaba, and a bank might someday include millions of globally distributed suppliers, vendors, and financial institutions. "Any sufficiently adopted permissioned chain starts to look a lot like a public chain," said Baldet, "and even though it might not be open to the entire world, you are only as secure as your most malicious member." The more robust the network, they suppose, the less risky it will be to do business in markets currently out of reach. It's this potential opportunity for top line revenue that gets Fortune 500s excited even more so than simply cutting today's paperwork load.

According to Nielsen, it's not as easy as it looks, "Building distributed blockchains is hard. It's hard to build privacy solutions that don't water down the trustless nature of the ledger. If you're going to introduce centralised services to make it easier, you might as well just use a distributed database. They're faster and already have enterprise support packages."

Talking to the teams in the middle of the design and coding process, it's easy to catch the excitement of people who believe their work might just change the world. At the end of the day, though, what exactly is J.P. Morgan trying to sell?

As to monetisation, J.P. Morgan insists they are committed to a long term view. If Quorum is Apple's iOS, then smart contracts are apps like Angry Birds. Giving away the operating system means there's a huge base to buy into new products later on, and therefore no plans to commercialise the existing platform. Possible interoperability with both public chain and other closed enterprise blockchains like those in development by IBM, Intel, Digital Asset Holdings, and a slew or others means Quorum can have their cake and eat it too. In a world where everyone insists it's still too early to pick blockchain protocol winners, flexibility is the name of the game. In the meantime, there are plenty of consortia hoping to nudge convergence along.

The Enterprise Ethereum Alliance (EEA) is a still-forming, non-profit trade organisation out to define standards so applications built on one Ethereum-derived platform run on another, and also ensure there is enterprise-grade tooling and support when corporates are ready to flip the switch.

While Quorum has been referred to as the jewel in the EEA's crown, the organisation insists it serves to foster a healthy community of enterprise-grade Ethereum solutions. Quorum's frontrunner status seems to have less to do with its corporate provenance and more with the focus that comes when users build the solution they need for themselves. "One of the key features we need for a blockchain to be used in enterprise settings is privacy. Incorporating zero knowledge cryptography to Quorum is a great step forward, since it makes Ethereum a lot more suitable to build enterprise grade solutions," said Julio Faura, Chair of the Enterprise Ethereum Alliance.

Before the announcement of EEA's formation, the price of Ether sat around $10 on cryptocurrency exchanges. Four months later, it is $262. Attribution of market fluctuation is a fool's errand, but a combination of enterprise interest, growing mainstream awareness, progress by the Ethereum Foundation on the core development roadmap, and irrational exuberance for Ethereum ICOs (initial coin offerings) is probably all contributing the upswing.