"[I'm] very much waiting for you guys to finish in a sea of shitcoins."

With that, pseudonymous forum user 'Monkeyyy' just might have summed up the sentiment surrounding a forthcoming cryptocurrency called "grin." Rising to renown last year as the first software implementation for a code proposal known as MimbleWimble, the idea is to start a new blockchain that has better scale and privacy than bitcoin.

That concept has won praise from developers who are normally wary of new ideas, namely because many of them don't turn out as great as promised (or otherwise devolve into get-rich-quick-schemes). But rather than coding their own solutions, grin's contributors are all about adopting technology that's been reviewed and approved by a circle of experts.

As the team wades into their second test stage, preparing to launch a working payment system, they've been among the first to implement Schnorr, Bulletproofs and Dandelion, all promising technologies originally intended to improve bitcoin's scale and privacy, but that just haven't made it into the hard-to-change cryptocurrency just yet.

Lead grin developer Igno Peverell, named after an obscure Harry Potter character, told CoinDesk:

"Testnet 2 was and is likely to stay our largest release in terms of new technology."

It's also ambitious. In turning MimbleWimble into a real, working software for payments, the developer team behind grin has added features that have been years in the making.

"Signature aggregation," for instance, has been in the works for bitcoin since 2014 and is one of its most highly anticipated code changes. Pioneered by Bitcoin Core contributor Pieter Wuille, the project "MuSig" has the potential to lump signature data together and free up space in the blockchain.

A working prototype has already been implemented, though it's unclear when it will be added to bitcoin and if the community will ultimately embrace the change.

Scalability boost

Therein lies one advantage of grin, which is more quickly putting such ideas to the test with real value.

Bitcoin is a living payment system, so developers and the community are particularly cautious when making changes that could be dangerous to its users.

"Bitcoin developers have working implementations of MuSig, but deploying it on the mainnet will take time. Actually, it must absolutely not be rushed," said cryptography expert Yannick Seurin, who's been helping with the cryptography behind MuSig at cybersecurity agency ANSSI.

But grin is launching a blockchain from scratch, so it's easier for the developer team to adopt sweeping changes - at least while the blockchain is still small.

"Since Grin is more experimental, they can afford testing newer primitives such as MuSig," Seurin continued.

It's worth noting though that in grin, signature aggregation plays a much more fundamental role. Unlike bitcoin, grin uses signature aggregation by default in transactions to remove data bitcoin normally has to keep to preserve the security of transactions.

Privacy boost

Then there's bulletproofs, a breakthrough privacy technology unveiled by bitcoin developers late last year.

Though bitcoin developers are worried about cryptocurrency privacy, and bulletproofs could help significantly with that, there are still major drawbacks. Bulletproof transactions are still too big. Even though the tech is more scalable, bulletproofs require a lot more room on the blockchain than normal transactions. And with users already very concerned about how big existing blockchains are getting, it would probably be pretty difficult to get agreement from everyone to make the change.

Other blockchains might not care about these downsides though. Privacy-minded monero and litecoin both plan to add this technology soon. And so does grin. Its developers are testing bulletproofs to help with its other main feature: enhancing privacy.

And while bulletproofs might be contentious in bitcoin, grin is a different story. For one, because of the above reliance on signature aggregation, grin is more scalable. So, bulletproofs increasing the size of transactions is not as big of a deal.

In fact, MimbleWimble was one use case that drove the innovation.

"Confidential transactions and Mimblewimble were one of the motivating applications for bulletproofs," Stanford University PhD student Benedikt Bunz, who pioneered bulletproofs, told CoinDesk.

That's not the only privacy technology they're adding, however. Peverell contends grin is the first cryptocurrency to adopt Dandelion, a long-proposed privacy addition to bitcoin.

Once someone sends cryptocurrency to someone using most blockchains, the transaction is sent to all nodes, without trying to hide where it came from. Because of this, it's easy to glean the IP address of whoever sent the transaction.

Dandelion introduces a second phase here called "fluffing" the transactions, which "makes it a lot harder to identify where transactions originate from," Peverell said.

Though, Bitcoin Core contributor Jonas Schnelli told CoinDesk he's optimistic bitcoin will eventually adopt the change, calling it a "pretty important" privacy feature. The reason it hasn't been implemented in bitcoin is no developers have had time to pick up the task just yet, he argued.

Toward reality

That's not to say there won't be significant hurdles.

One rather huge drawback of MimbleWimble's approach is that in order to get the scalability and privacy benefits, transactions are much simpler than bitcoin's. That means, it makes it harder to do more complex types of transactions, like requiring two or three people to sign off on a transaction before it can be sent, or to build more scalable infrastructure, such as lightning network, on top of it.

There's still hope, though.

Peverell is excited about signature aggregation because it can pave the way for still other future technologies, such as scriptless scripts, a technology that could reintroduce a way for users to do these types of complex transactions using grin.

According to Peverell, most of the technical heavy lifting will be out of the way once they finish their second testnet.

But there are a number of steps left before they can be sure there aren't any problems with the payment system and they're ready to launch. Peverell noted grin is launching yet another testnet (their third) to finalize some changes and stomp out as many bugs as possible.

The loose volunteer team also wants to build out the wallet to be more "user-friendly," since being easy to use is something cryptocurrencies tend to struggle with. And finally, they want a third party to audit Grin's code.

This sounds like a lot, but Peverell hopes they'll be able to launch the payment system for real by the end of the year, at which point the team can put the experimental concepts its trial to test in a live environment with real funds.

He stated:

"I'm still optimistic for this winter."

Microscope image via Shutterstock

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