Ethereum's consensus algorithm isn't the only thing that changes with the launch of Eth 2.0. The underlying cryptography itself is being overhauled based on cutting-edge research from the Electric Coin Company.

Called BLS12-381, the new elliptical matching curve will securely coordinate transactions on the Eth 2.0 Proof of Participation (PoS) network, while opening up opportunities for data savings and privacy solutions. 

Currently, the ins and outs of this curve are integrated into the network with the Ethereum 2537 improvement proposal. EIP delivery is scheduled with the 10th hard fork of the protocol, Berlin, tentatively scheduled for July.

As a hard fork, Berlin will add up to four upgrades incompatible with k-bins, two of which continue to be verified and may ultimately not be included (all of this is unlikely since all four EIPs are implemented works at different levels by each Ethereum client). 

A test network, Yolo, performing dry tests without applications, is currently underway for EIP 2537 and another proposal, EIP 2315, which will add "simple routines" to the Ethereum virtual machine (EVM).

For Eth 2.0, EIP 2537 is an introduction to the interesting cryptography work that underpins the new network while answering a question that Ethereum co-founder Vitalik Buterin has pondered since the early days of the network.

From 1.x to 2.0

To launch Eth 2.0, a technical bridge must exist between Eth 1.x and Ethereum's existing Eth 2.0 . 

BLS12-381 underpins such an option by building an Eth 2.0 "thin client" inside the current Ethereum network , according to an April Medium article by Ethereum developer Alex Stokes.

In short, Eth 2.0 will be rolled out in stages, starting with phase 0 in the third quarter of 2020. Phase 0 will start with the tag chain, a coordinating mechanism for investors staking funds. In PoS networks like Tron or EOS , staked funds function as a voting mechanism and an incentive to participate in the verification of transactions.

Eth 1.x runs on the Proof-of-Work (PoW) algorithm and has a fully separate cryptographic scheme called Elliptic Curve Digital Signature Algorithm (ECDSA), also used by Bitcoin and other cryptocurrencies

But to connect the PoW and PoS networks, a common language is necessary. 

This is what EIP 2537 does - by providing a cryptographic translator between the two networks in what is called a precompilation of the underlying primitives of Eth 2.0. This precompilation makes a thin client possible.

In practice, a thin client would be built like a smart contract inside the EVM. Its main objective, given the limited functionality of the client, would be to carry the ether ( ETH ) on the new chain, a prerequisite for the embarkation of people on the new network.

Additionally, Layer 2 (L2) solutions for scaling Ethereum and Eth 2.0 could be built on the Lite client, said Ethereum co-founder Vitalik Buterin in an article. published in April on Ethereum Magicians

“If we have that, then an eth2-in-eth1 client is actually not that difficult, which opens the door to applications that use eth2 as an availability engine (ie things like Plasma but more powerful waaay), ”wrote Buterin.

Find the right primitive

The next iteration of Ethereum has far greater ambitions than ECDSA can manage. Fortunately, 10 years of research into cryptocurrencies has paid off in at least one subject: cryptography itself, Cloudflare cryptographer Nick Sullivan said in an interview. New curves like BLS12-381 prove it.

"Elliptical curves have been around since the mid-1980s," said Sullivan. “The problem is that they are somewhat limited in what they can do. They can efficiently perform conventional public key operations: digital signatures, encryption and key agreement. "

Alternatively, the "friendly pairing" curves invented in the early 2000s provide alternative safety measures that rightly apply to blockchains, said Sullivan.

Invented in 2017, Sean Bowe's BLS12-381 from Electric Coin Company, a variant of the BLS curve invented by three crypto pioneers in 2003, is perhaps the most important for most coins today. Its curve, and others like it, are the reason why blockchains can evolve.

"BLS12-381 is a special type of elliptic curve (a" compatible with matching "curve) that allows cryptographic primitives like SNARK and vector engagement schemes," Bowe said in an email. "These primitives are very useful for improving scalability and confidentiality in blockchain projects."

BLS and Eth 2.0

For Eth 2.0, the advantage can be divided into three parts: data economy, confidentiality and interoperability.

First, BLS-style signatures keep the necessary computational light by grouping cryptographic signatures that verify transactions, according to Ethereum researcher Carl Beekhuizen in a blog article by the Ethereum Foundation . 

Beekhuizen wrote:

“If 10% of all ETHs end up staking, then there will be around 350,000 validators on eth2. This means that the value of signatures from an era would be 33.6 megabytes, or about 7.6 gigabytes per day. In this case, all the false allegations that the   size of the eth1 state would reach 1 TB in 2018   would be true in the case of eth2 in less than 133 days (based on signatures only). "

(For reference, this is almost three times the weight of the current Bitcoin blockchain .)

BLS12-381 also allows Eth 2.0 to implement proofs of zero knowledge more naturally: the confidentiality variants of ETH could be native to Eth 2.0. In fact, BLS12-381 has been hard forked in the Zcash protocol with the 2018 Sapling update as a more robust cryptographic primitive.

In addition, the use of ECC technology on Ethereum highlights the close relationship between Buterin and Zooko Wilcox, co-founder of Zcash and CEO of ECC. The ECC and Zcash teams have both shown a past interest in bridging the two technologies.

Third, the proposal opens up interoperability between different channels such as Filecoin, Chia or Algorand and Eth 2.0, a long-standing promise from several other blockchain networks such as Polkadot, which announced the launch of its main network earlier this month -this. 

The ability of Eth 2.0 to connect to other projects - especially those that are not Bitcoin - could materialize in different ways: perhaps Ethereum shares its value between different channels or perhaps siphons the technology of other projects, taking with them their market capitalizations.

Anyway, Cloudflare's Sullivan remains impressed with the math:

"This is a really fascinating curve of how things are going - mathematicians and cryptographers wrote about it in academic articles, and people from the world of engineering have begun to implement and test the , then it is introduced into projects and protocols, then becomes part of society. And then you find yourself in this position where there are so many different options that it's hard to know exactly which one to choose and why. "