Mimblewimble coins challenge the crypto privacy status quo

Mimblewimble — the privacy protocol named after the tongue-tying curse from Harry Potter — has finally been implemented on a live network. Beam, the first of two cryptocurrencies built using Mimblewimble, went live on January 3rd, and is expected to be followed by contemporary Grin on January 15th. Each offer slightly different implementations of the protocol that promises to make privacy scalable.

According to CMO Beni Issembert, the name Beam can be thought of as "a crossbeam between the crypto world and the rest of the humanity" — a vision that has attracted a reported $4 million in funding from venture capital firms Continue Capital, Ceyuan, 1kx, Node Capital and others, who have helped the non-profit foundation develop before it can derive an income from mining rewards. This approach mirrors coins like Zcash, and has helped propel the project forwards in the race to implement the first blockchain-based on Mimblewimble.

Rival coin Grin, which is named after Gringotts Wizarding Bank from the Harry Potter stories, takes a more communal approach to development like its ideological forefathers Bitcoin and Monero. Grin is maintained by no single body, but relies on donations and the selling of merchandise to feed a scattered group of developers. Unlike Beam, all Grin code is open source in keeping with the cypher punk ethos.

Aside from differences of governance, the coins also use different programming languages and consensus algorithms, and claim to be pursuing slightly different positions in the privacy niche: similar to Zcash, Beam offers a flexible version of privacy where users will be able to decide for themselves "which information will be available and to which parties", whereas like Monero Grin will offer privacy by default.

But what makes Mimblewimble so special? And why are some commentators suggesting that Grin and Beam are at the "cutting edge" of cypherpunk protocols"?** **

Mimblewimble magic

In a move reminiscent of Satoshi, the Mimblewimble whitepaper was dropped on a bitcoin research channel by ‘Tom Elvis Jedusor’ (the French version of the dark lord Voldemort from Harry Potter). But despite being named after a spell and delivered by a wizard, Mimblewimble

relies only on complex cryptography to mask transactions.

Put simply, the protocol represents a new approach to creating scalable privacy coins that reconciles the often antagonistic aims of privacy and scalability.

Because privacy-oriented blockchains often include extra cryptographic features — like the ring signatures of Monero and the zero-knowledge proofs of Zcash — they can be weighed down and more difficult to scale effectively. This is where Mimblewimble offers a solution: the protocol takes the original bitcoin architecture and cuts away parts of the chain — like Scripts — in accordance with principles from CoinJoin, a style of transacting originally proposed by Greg Maxwell in 2013.

Although the Mimblewimble codebase remains somewhat true to the original structure of bitcoin, the way transactions are processed is very different, as explained by BEAM CTO Alex Romanov: "the [Mimblewimble] protocol manages to resolve the problem of privacy without adding additional information to the blockchain, but quite the opposite — making it smaller and more efficient".

With this slimmed down version of the protocol, the private transaction mechanism cannot weigh the blockchain down, making Mimblewimble of interest to developers keen to create standalone implementations of the tech — like Grin and Beam — and also experiment with using the protocol as a sidechain to bitcoin. This was initially proposed a few months after the white paper appeared in 2016, and would theoretically allow bitcoin to be shifted on to sidechain to transact with an increased level of privacy.

Grin and Beam

It wasn’t until the end of 2016 when another Harry Potter character appeared — Ignotus Peverell, the inventor of Potter’s invisibility cloak — with an implementation of the protocol called Grin. This cryptocurrency uses the programming language Rust, which is known for its

speed and scalability, and a consensus algorithm known as ‘Cuckoo cycle’ that aims to minimise potential centralization with ASIC-resistance.

Work began on Beam project shortly afterwards, and the project — which is based on C++ like Bitcoin Core — developed more quickly than its contemporary. Despite a few hiccups with the wallet, the project now appears to be spreading its wings, with some sources suggesting that the coin has already secured a third of pioneering privacy coin Monero’s hashrate.