Onchain Blind Auctions Using Homomorphic Encryption and the fhEVM

Blind auctions, traditionally challenging to execute in smart contracts due to public transaction and state data, can now be fully conducted on-chain using homomorphic encryption and the fhEVM, eliminating the need for a reveal function. The outlined protocol involves a bidding and claim phase where users bid encrypted ERC20 tokens, allowing the contract to homomorphically determine the highest bidder while maintaining bid privacy. The smart contract employs FHE data types to keep bids hidden and uses homomorphic comparisons for operations typically requiring conditionals. After the auction, the winner can claim their prize, and non-winning participants can withdraw their bids without revealing bid values. This approach enhances security and privacy, streamlining the auction process by replacing the reveal step with a claim function.