Ever since Bram Cohen first ventured into the world of cryptocurrency, fans of decentralized technologies have eagerly awaited what the creator of the BitTorrent file-sharing protocol would deliver.

But Cohen is in no rush.

For the last two years, he’s been quietly working on what he believes is the future of digital money—a faster, cleaner, more decentralized version of Bitcoin, called Chia.

It’s made possible by a new and unique consensus mechanism that Cohen refers to as “proof of space and time”—an alternative to the energy-guzzling proof of work that underpins networks like Bitcoin and Ethereum that instead relies on the excess storage space on hard drives to verify its blockchain.


Now, after nearly 24 months of building, testing, and harnessing the wisdom of the crowd through big-dollar coding competitions, Cohen is finally ready to let the world get a good look at what makes Chia tick.

The Chia Network, the company co-founded by Cohen that is building the Chia protocol and blockchain network, today released its long-awaited “Green Paper”—a technical whitepaper that fleshes out Chia’s dual proof of space and proof of time consensus mechanism and explains “what needs to be done in order to make a proper Nakamoto-style consensus blockchain,” Cohen said in an interview with Decrypt.

But while the release of the Chia white paper might signal a significant step in the cryptocurrency’s development roadmap, the protocol itself hasn’t yet been perfected, Cohen explained. To do that, the Chia Network is launching yet another $100,000 coding competition that Cohen hopes will entice developers to vie to create the best possible implementation of Chia’s proof-of-space algorithm.

Cohen said his company has had great success with these sorts of competitions over the past year. The Chia Network has held two “Verifiable Delay Function competitions” that sought to fine tune Chia’s proof-of-time algorithm, with each round exponentially improving on the last implementation, Cohen said.


“As much as possible, we’d like for everyone in the world to be aware of these things, because you never know who’s going to turn out to be really, really good at this stuff,” said Chia’s founder. “That’s the whole point of offering prize money. The best person out there who you’ve never heard of before has the opportunity to win the whole thing.”

Cohen said that it would have been impossible for Chia to have made the progress that it has on its proof-of-time algorithm without these competitions. The hope is that this latest blockchain coder battle royale will deliver that same magic for Chia’s proof of space.

Meanwhile, the release of Chia’s Green Paper will at last allow both developers and academics to get a detailed look at Chia’s fundamentals—the building blocks behind a cryptocurrency that promises all the benefits of Bitcoin without any of the drawbacks.

After all, a cryptocurrency that is “farmed” (rather than mined) on a blockchain by filling excess hard drive space with proofs, while disincentivizing CPU energy usage and centralized mining pools, isn’t an easy thing to wrap one’s head around—and neither is the math that backs it up, Cohen admits. (For a full-blown explanation of Chia's algorithm see our previous writeup here.)

“Thus far, the materials that we’ve made available have been sufficiently sketchy that the academic world hasn’t felt ready to pass judgement about whether we’re smoking crack with what we’re doing,” he said with a laugh.

The Green Paper, however, “makes it possible for academics to review what we have as a real thing and pass judgement on whether this really makes sense or not,” said Cohen. “There’s enough information there that they could really build the whole thing themselves using what we’ve published—just probably not as well as we could.”

Cohen said Chia’s whitepaper, though still highly technical, is “much more approachable” than the company’s previous materials and fully explains how Chia’s proof of space and time is stitched together “to make a secure Nakamoto consensus.”

Fans of Bitcoin may also find value in the whitepaper, according to Cohen, since it “also does a better job of anything out there of explaining some of the really important parts of Bitcoin, like work difficulty resets,” he said.


While Chia’s goal might be to get cryptocurrency “away from the proof of work that Bitcoin uses, because it’s very wasteful and nowhere near as decentralized as we’d like,” said Cohen, the inventor of BitTorrent is still highly reverent of Satoshi Nakamoto’s creation.

Chia has in the past been called a “Bitcoin killer,” given its ambitious tack, but Cohen said he wants no part in pushing that narrative. “As I see it, [Chia] is part of the same research project which is bitcoin.” The idea, he said, is to take the things we’ve learned from Bitcoin and build from those lessons.

“Let’s go over everything we know about bitcoin and how it works, and then ask ourselves, ‘What if we weren’t stuck with a legacy codebase?’ What would we do then? And that’s really the approach we’re taking here,” he said.

Cohen believes the blockchain industry today remains full of “some completely, obviously scammy cryptocurrencies with multi-billion-dollar market caps,” but suggests that it might not be so difficult to separate the wheat from the chaff in crypto.

“To my mind, the thing that cryptocurrencies are really good for is commerce—like, actually being used as money. And everything that I’m working on here is how to make them be better as money.”

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