What Grin and Mimblewimble Mean for the Future of Bitcoin Privacy
In a little over a month, one of the most eagerly anticipated cryptocurrency projects in recent times will launch. There will be no ICO or premine, and, like the transactions themselves, the project team are highly private. Grin, the first network to utilize Mimblewimble cryptography, has wide-ranging implications for privacy that could ultimately shape the future of the Bitcoin network.
Grin and Beam Will Give Privacy Purveyors a Lot to Smile About
Grin and Beam are two projects that will make use of Mimblewimble, a form of cryptography whose applications include facilitating private transactions. Of the pair, Grin has garnered the most attention from bitcoiners. One reason for this is that the success of new privacy protocols could pave the way for Bitcoin Core or Bitcoin Cash to adopt similar tech. That possibility remains some way off, but in the meantime, there are other reasons why Grin has intrigued the Bitcoin community.
Observers have noted the similarities between the launch of Grin with that of Bitcoin and Monero. Grin has a largely anonymous team, no founders’ rewards, and a community spirit that harks back to the early days of Bitcoin, when proponents were more interested in creating something useful than posturing and profiting. While Grin will certainly attract its share of speculators, its technology is its primary talking point. “Grin has no amounts and no addresses,” explains its website. “Transactions can be trivially aggregated … It’s not controlled by any company, foundation or individual. The coin distribution is designed to be as fair (but not gratis) as is known to be possible.”
The Magic and Mystery of Mimblewimble
At the heart of Grin, as well as Beam, the latter described as a “Scalable confidential cryptocurrency,” is Mimblewimble. Named after a Harry Potter spell also known as the Tongue-Tying Curse that prevents an opponent from casting theirs, Mimblewimble enables the bulk of a blockchain’s past transaction data to be removed. It first surfaced on the #bitcoin-wizards IRC channel back in 2016, proposed, fittingly, by a pseudonymous developer known as Tom Elvis Jedusor, named after Voldemort’s real name in the French edition of Harry Potter.
Intriguing as Mimblewimble’s origins are, it’s what the so-called Tongue-Tying Curse can do in the here and now that’s had tongues wagging. “Mimblewimble collapses all transactions within a block into a single block-wide transaction,” explains Jordan Clifford in “Behind Mimblewimble”. He continues: “It uses a modified version of Confidential Transactions so that the balances are stored as cryptographic commitments rather than publicly visible amounts.”
Because Mimblewimble does away with conventional addresses, sender and receiver essentially have to agree to transact before broadcasting their actions to the network. With the amount that has been sent masked, it is extremely difficult for third parties to eavesdrop. This is in stark contrast to networks such as Bitcoin, where “blockchain voyeurism” is a very real thing.
What Mimblewimble Means for Bitcoin
Like many cryptographic technologies to have emerged over the last decade, Mimblewimble’s origins can be traced back to Bitcoin. For one thing, it uses Dandelion, a technology that was originally designed for Bitcoin, as a means to obfuscate transactions by routing them through a series of network hops. Due to the decentralized design of Bitcoin, network upgrades are few and far between. “Move slow and break nothing,” is basically the mantra.
Bitcoin is still a long way from introducing privacy-enhancing technology, and there are many who believe that, due to pressure from institutional investors and regulators, it may never be possible to broadcast fully anonymous transactions directly on the BTC blockchain. Schnorr signatures, a scaling technology which can help to combat spam attacks, have a greater chance of being introduced first. This could provide a stepping stone, however, for the addition of Coinjoin or alternative privacy tech based on Mimblewimble.
Given the potential applications for a Bitcoin network with optional private transactions, it’s no wonder that Grin and Beam are attracting so much interest. The Beam mainnet launch is due this month, while Grin’s is set for Jan 15, 2019. Both networks will provide a fascinating insight into the capabilities of Mimblewimble, two and a half years after it was conceived.