EthDam 2025 wrapped last week, and the hackathon submissions? Honestly impressive. This wasn’t your average “just slap a frontend on a wallet” kind of event—devs came in hot with legit use cases for private compute, encrypted ownership, and confidential UX.
If you’re into confidential smart contracts, verifiable offchain logic (ROFL), or building tools where users actually control their data, read on.
🧠 The Stack Behind the Hacks
Most projects were built using:
- 🛡️ Sapphire — Oasis’s EVM-compatible chain with TEEs for confidential smart contracts
- 🤖 ROFL (Runtime Offchain Logic) — Containers that run encrypted computation offchain and send proofs onchain
- 📦 Trusted Environments — Intel SGX, enclave execution, tamper-proof storage
This combo lets you write apps that:
- Process private data without ever decrypting it publicly
- Run logic offchain, but verify the output onchain
- Enforce logic with no backdoors—even devs can’t cheat it
So what did teams build with this?
🥇 Winning Projects & Themes That Emerged
🔐 Privacy-Preserving Communication
🧵 ROFL.Dam
A decentralized chat platform with no central servers, full user-side message control, and end-to-end privacy—built entirely using ROFL. Unlike Signal or Matrix, ROFL.Dam gives you the platform and the backend in one verifiable, self-sovereign package.
→ Think of it like: P2P Signal + verifiable TEEs + no trust assumptions.
🧬 Secure, Monetizable Health Data
🩺 HealthTrust
Patients upload encrypted health records. Researchers run ML on them. Nobody sees the raw data. Patients get paid. Built with ROFL + Sapphire, this flips the current health data model on its head—data stays private, compute goes to the edge.
→ This is the holy grail of decentralized bioinformatics. And they demoed it.
🕹️ Onchain Games With Real Privacy
👾 MonCraft
Retro RPG + onchain monsters + privacy-preserving battles and randomness. Powered by Sapphire and ROFL, MonCraft proves that you don’t need to expose every move onchain to build a fair game.
→ Onchain RNG that isn't exploitable. Combat state hidden. Monsters you can catch but not front-run.
🌉 Trustless Fiat ↔️ Crypto
💸 RØPE
A non-custodial on/offramp that lets users swap fiat ↔ crypto without KYC or a centralized exchange. Encrypted payment proofs. Verified email receipts. Funds auto-release when conditions are met.
→ If built out, this could be a big deal for unbanked and underbanked onboarding.
🤝 P2P Escrow with Real-World Verifiability
🔐 ZK-Pal
Trustless USDC for PayPal trades. Sapphire smart contract locks funds, while a ROFL enclave parses a PayPal email confirmation inside a TEE to release funds. No escrow middleman. No screenshots. No BS.
→ This kind of hybrid real-world validation is what privacy infra needs more of.
⚰️ Decentralized Inheritance
📜 Testament
You define your heirs. Data stays encrypted. A trigger mechanism (like your death, verified by executor) unlocks your assets to the right people—automatically. All logic is sealed until it matters.
→ Think of it as a private onchain will system. Clean, tamper-proof, dead man’s switch logic.
⚙️ Secure Offchain Computation Market
🧮 ChainLab Grid
You provide encrypted data. Someone else provides CPU. You both stay private. ChainLab Grid makes this handshake verifiable with ROFL, turning computation into a secure, token-incentivized market.
→ Basically: AWS Lambda, but encrypted, decentralized, and peer-to-peer.
🧑💻 Anon Tools for Activists
🧰 Activist Toolkit
Anonymous proof-of-presence, emergency alerts, encrypted credentials. This is privacy tech for protestors and human rights defenders. Built on Oasis with strong encryption and no onchain trail.
→ Real-world need. Real-world relevance. No fluff.
📈 Privacy in Prediction Markets
🎯 P.I.M.P. (Private Insight Market Protocol)
A confidential copy-trading system. Experts publish encrypted strategies, and subscribers follow without seeing the alpha. No front-running. No leaks.
→ Traders stay private. Newbies get gains. It’s win-win.
If you’re building anything offchain, encrypted, or zero-trust—bookmark those docs.
🎉 Final Thoughts
Hackathons often crank out flashy ideas that never go anywhere. This one felt different. A lot of the projects here solve real problems that need privacy-first tooling.
Even cooler: a lot of this tech is open for devs to build on right now.
You don’t need to wait for some VC-backed rollout. You can fork MonCraft. You can build your own P2P verifier for ZK-Pal. You can plug ROFL into your existing dapp to run encrypted compute offchain.
🛠️ Ready to Build?
Here’s where to start:
- Join the Oasis Discord
- Docs for Sapphire
- Fork the Sapphire template
- Try the ROFL sandbox
- Follow Oasis on X for future hackathons
Let’s build the tools that Web3 actually needs.
Top comments (1)
Touted as hacker speed dating, the ETHDam hackathon is fast gaining legendary status for its IRL non-stop hacking and developing. The introduction of the ROFL framework has been a game-changer during the recently concluded edition. The technical workshop in the lead up to the hackathon had me excited, and the winning projects justified the anticipation. Also, loving the links to the demos of the winning projects - this will certainly inspire and benefit the next crop of devs working with Sapphire and ROFL.
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