The challenge

Traditional DeFi vaults publish every user balance and yield figure openly on-chain. Implementing ERC-4626 vaults under Fully Homomorphic Encryption required cryptography patterns that had no established reference implementation.

The approach

Integrated the Fhenix CoFHE coprocessor with the vault contracts so deposits, shares and yield accrue as encrypted integers (InEuint64). Arithmetic runs on ciphertext, and balances are never decrypted on-chain.

What we did

• //001FHE-encrypted vault shares (InEuint64)
• //002Automated yield routing engine
• //003Confidential deposit & withdrawal proofs
• //004Arbitrum Sepolia coprocessor integration

The outcome

Pioneered an implementation of Fully Homomorphic Encryption inside decentralised finance smart contracts.