Fully homomorphic encryption rollups are one step closer to reality

Fhenix, a possible layer-2 community that wishes to deliver totally homomorphic encryption (FHE) to sensible contracts, has revealed a technical white paper for the primary FHE rollup.

FHE itself is a type of encryption that ensures the confidentiality of the info even whereas it’s getting used, for instance in sensible contracts, as a result of information can stay encrypted and processed with out ever needing to be decrypted.

This permits Ethereum and different EVM networks to course of data privately, with potential functions associated to non-public voting and confidential gaming — equivalent to poker, for instance.

Learn extra: Encryption startup Fhenix raises $7M for personal computation

Not like zero-knowledge (ZK) know-how, FHE is totally personal, Fhenix CEO Man Itzhaki informed Blockworks.

“With ZK, there may be an entity known as a prover that really sees the data,” Itzhaki explains, “so confidentiality arises from the truth that this prover is being positioned on the person aspect, producing the ZK proofs.”

One limitation is that it precludes use circumstances requiring computation on information that comes from a number of customers, he mentioned.

This isn’t the case for FHE-based techniques, Itzahki mentioned. With FHE, information and computation is completed on-chain, with out the necessity for a prover or one other entity.

“Our general imaginative and prescient at Fhenix is to create an FHE stack that may enable builders to construct functions with information confidentiality, and for customers to learn out of those functions by growing their degree of safety and privateness,” he mentioned.

FHE in and of itself goes past simply safeguarding privateness, Man Zyskind, the founding father of SCRT Labs (the group behind the Secret Community) informed Blockworks.

“This isn’t nearly defending folks’s privateness — lack of on-chain encryption is the rationale why we’re very restricted within the functions we will construct on blockchains at present. As an example, think about creating an on-chain poker sport. With out encryption, gamers’ palms could be seen to all, rendering the sport unplayable,” he mentioned.

Zyskind notes that current privacy-focused blockchains rely closely on zero-knowledge proofs, which fall quick with regards to the combination of personal information from a number of sources, equivalent to in an on-chain poker sport or a sealed-bid public sale contract.

“Zero-knowledge proofs are extra suited to single-user situations, equivalent to verifying age with out revealing the precise start date. In these circumstances, zk proofs are efficient however inadequate for complicated, multi-party personal information integration, the place FHE rollups develop into important,” he mentioned.

Utilizing an optimistic rollup construction

The FHE rollup white paper outlines using an optimistic rollup construction, a choice, Itzahki notes, which is able to allow the rollup to be each scalable and personal.

Though utilizing a zk rollup structure isn’t totally out of the query, Itzahki explains that it will be tough to create a rollup resolution that mixes two very heavy-duty cryptographic techniques.

“At this time second, the implementation of FHE by way of optimistic [rollup structures] is far more environment friendly,” he mentioned.

One of many key breakthroughs for Fhenix was devising an efficient mechanism for fraud proofs when utilizing an optimistic rollup.

Learn extra: So your layer-2 is ‘secured by Ethereum’ — what does that imply?

Itzahki explains that the group was in a position to introduce a fraud-proof mechanism utilizing internet meeting, a low-level computing language, which is able to allow fraud verification to be enacted in the identical manner as if the info was not encrypted.

“Slightly than [running] on the native EVM itself, that mechanism permits us to test if that internet meeting code as change, and lets us know if there’s a fraudulent transaction,” he mentioned.

Modular design

The FHE rollup shall be designed modularly, that means that it’ll draw from totally different elements to create the blockchain.

“We’ve a separation between the sequencer, validator, and the info availability layer,” Itzahki mentioned. “The info availability layer is usually Ethereum, then we at Fhenix will deal with the sequencer and handle the execution, the validator, and the prover.”

Having a modular design will allow cryptographic improvements equivalent to FHE to execute extra effectively, enabling it to concentrate on its strengths the place wanted.

“We don’t essentially must have [FHE] all through your complete elements. In order that’s why we’re going with a modular design,” Itzahki provides.

Kyle Samani, managing companion at Multicoin Capital, an investor in Fhenix, mentioned the protocol’s rollup is a first-of-its-kind layer-2 that may deliver FHE on-chain in a usable manner.

“The white paper is a essential first step in serving to builders understand that L2’s can be utilized for extra than simply scaling. They’ll now be used to increase the performance of functions into new design areas,” Samani mentioned.

Fhenix plans to launch the testnet of its first FHE rollup within the first quarter of 2024. It’s undecided whether or not the rollup stack shall be constructed open-source, although testing shall be accessible to any tasks.