Fhenix: FHE Coprocessor on EigenLayer

Fhenix and EigenLayer Join Forces to Pioneer FHE Coprocessors, Revolutionizing Onchain Confidentiality on Ethereum

We are excited that FHE Coprocessor will be building on EigenLayer and to announce the development of FHE-based coprocessors in collaboration with Fhenix.

FHE coprocessors are secured by Fhenix’s optimistic FHE rollup infrastructure and EigenLayer’s restaking mechanism. 

What are Coprocessors?

A coprocessor serves as a companion processor designed to offload specific computational tasks from a host chain – whether it’s Ethereum, an L2 or an L3, to a designated processor living outside the scope of the host. Unlike ZK coprocessors, which are tailored for scaling computations off-chain, FHE coprocessors specialize in maintaining data confidentiality during computation, which opens up new applications that are not otherwise possible. 

Understanding the FHE Coprocessor Architecture

FHE coprocessors are effectively stateless, lightweight FHE Rollups in disguise. By stateless, we mean that they get inputs directly from the host chain (or from a user calling the coprocessor directly), rather than storing a state in by themselves. This makes the coprocessor a more lightweight construction, that can remain idle until it is needed to perform specific tasks. Furthermore, being stateless, we can greatly optimize the performance of these computations by using leveled FHE schemes.

For efficiency reasons, FHE rollups rely on fraud proofs (as opposed to ZK proofs). These proofs are settled on the host chain directly, ensuring the host chain and coprocessor share security. A coprocessor can have robust security mechanisms by building an AVS which uses restaked ETH as security collateral.

Interacting with an FHE coprocessor is simple: an application on the host chain invokes (through an on-chain relay contract and an off-chain relay node) the coprocessor, asking it to perform some specific computation over a set of encrypted inputs, and gets the result back, which it can continue to use on-chain. The full flow is illustrated above and includes the following steps:

  1. An application contract on the host chain invokes an encrypted computation in the FHE Coprocessor.
  2. Our relay contract queues the request.
  3. A relay node listens to events in the relay contract, and bridges a call to a dedicated Fhenix rollup.
  4. A (stateless) FHE rollup executes the computation over the encrypted inputs.
  5. The threshold network decrypts the output.
  6. EigenLayer operators verify the execution and send partial signatures to a relay node.
  7. A relay node calls back the contract with the result and an aggregated signature.
  8. The relay contract verifies the aggregated signature and passes the output to the calling contract, relying upon EigenLayer for cryptoeconomic security. Any honest node may still submit a fraud proof within the dispute window (e.g., 7 days), in which case a dispute process would commence should there be any disagreement.
  9. The application contract can resume execution, utilizing the result.

The Significance to the EigenLayer Ecosystem

EigenLayer allows any AVS to inherit security from Ethereum restakers. In theory, FHE coprocessors could use EigenLayer to gain a cryptoeconomic guarantee on the correctness of the execution done by the FHE rollup. EigenLayer operators would attest to the validity of executions, but should any operators be malicious, their stake would be slashed.

This is how fraud proofs can be confirmed immediately, removing the need to wait until the end of the fraud proof period (typically 7 days). This means that FHE coprocessors can at last compute at a rate once considered impossible, marking a major milestone in the advancement of on-chain FHE.

It’s also representative of the serious technological impact that an AVS can have, and a profound use case of EigenLayer. This is why we are particularly excited for this collaboration and are investing significant resources.

New Applications Horizon

The application spectrum for FHE coprocessors extends across a diverse array of scenarios, particularly in domains where preserving confidentiality is paramount. 

Take, for instance, the application of FHE in on-chain auctions, where bid confidentiality ensures fairness and a more economical outcome for all bidders. Similarly, with on-chain AI, FHE coprocessors can run intensive computations away from the host chain, all the while ensuring that the input data is kept private. The full list of use cases is extensive and includes decentralized identity, confidential DeFi, encrypted gaming, MEV protection, and much more.

This is why we consider this partnership to be of substantial significance and is particularly exciting from an AVS use case perspective.

A Future Shaped by FHE coprocessors

This collaboration marks a significant milestone for Ethereum.

By harnessing the power of FHE coprocessors, developers can build applications that utilize confidential data securely and efficiently, while maintaining security. This technological advancement opens up new possibilities for confidential blockchain applications and represents a significant AVS use case.

We look forward to our commitment to this endeavor and see confidential computation as a revolutionary area of blockchain.

About EigenLayer

EigenLayer is a protocol built on Ethereum that introduces restaking, a new primitive in cryptoeconomic security. Restaking enables staked ETH to be used as cryptoeconomic security for protocols other than Ethereum, in exchange for protocol fees and rewards.

For more information visit www.eigenlayer.xyz/ 

About Fhenix

Fhenix is the first FHE-powered L2 to bring on-chain confidentiality to Ethereum. Fully Homomorphic Encryption, or FHE, is a novel cryptographic scheme that enables direct computation over encrypted data without ever revealing the underlying data. Fhenix extends Ethereum’s capabilities with the goal of advancing application development and bringing true data confidentiality to smart contracts, transactions, and on-chain assets for the first time.

For more information visit www.fhenix.io