ShadowBid — Encrypted Sealed-Bid Auction (FHE)
On-chain sealed-bid auction dengan Fully Homomorphic Encryption (FHE) — bid tetap terenkripsi, smart contract compute winner tanpa decrypt. 47 tests.
Context
A custom build where the business flow mattered more than plugging in a generic template.
Project at a glance
Protokol sealed-bid auction dimana bid tetap terenkripsi on-chain menggunakan FHE. Problem: on-chain auctions biasa vulnerable ke MEV extraction, bid sniping, dan price manipulation karena bid visible di mempool. Solution: bid di-encrypt di browser via CoFHE SDK, smart contract bandingkan encrypted bids via FHE CMUX operations tanpa pernah decrypt — hanya pemenang yang di-reveal setelah settlement via Threshold Network. Deployed on Arbitrum Sepolia.
What this case helps prove
The challenge
On-chain auctions biasa (English, Dutch, Sealed-bid) semuanya vulnerable: bid visible di mempool, MEV bots bisa snipe, dan price manipulation mudah dilakukan. Tidak ada privacy untuk peserta auction.
The response
Fully Homomorphic Encryption (FHE) memungkinkan smart contract compute pada encrypted data. Bid di-encrypt di browser via Fhenix CoFHE SDK, disimpan on-chain sebagai euint64. Smart contract bandingkan encrypted bids via CMUX operations — tidak pernah decrypt individual bids. Hanya winning bid yang di-reveal setelah finalization via Threshold Network.
Why it mattered
Deployed on Arbitrum Sepolia testnet (contract: 0x96dA...447)
Before and after, in clearer terms
The point of this section is not decoration. It is to show the operational shift in terms the client team can immediately recognize.
Bid privacy
Before
Visible di mempool — MEV extractable
After
FHE encrypted — zero knowledge sampai settlement
Winner selection
Before
On-chain comparison (plaintext)
After
CMUX on encrypted bids — never decrypts losers
Trust model
Before
Trusted auctioneer atau transparent (gameable)
After
Trustless — verifiable on-chain, no third party
Key highlights of the build
Fully On-Chain Encrypted Bidding
Bid di-encrypt di browser via CoFHE SDK dan disimpan on-chain sebagai euint64. Smart contract compute winner via FHE CMUX tanpa pernah decrypt individual bids — eliminating MEV, bid sniping, dan price manipulation
Zero-Trust Auction Settlement
Tidak butuh trusted third party atau off-chain computation. FHE protocol enable verifiable on-chain settlement dimana hanya winning bid yang di-reveal setelah finalization via Threshold Network
Full Auction Lifecycle + Institutional UI
Complete auction flow: create → bid → finalize → reveal → claim/settle. Polished institutional dark-theme design system dengan 11 purpose-built pages, responsive layouts, dan comprehensive empty states
Impact that stayed visible
What the system includes
Technology stack
Frontend
Smart Contracts
Integrations
Architecture
If this kind of operational shift is what you need, start from the problem.
The fastest useful next step is not asking for a random feature list. It is clarifying what feels weak today, what friction the team still carries, and what a cleaner first version should solve.