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ETHDam Hackathon: “Build Natively on Sapphire” Bounty Winners

With $12,000 in prizes on the line, the competition was fierce and packed with excitement and innovation.

In the heart of Amsterdam, Oasis was proud to launch the “Build Natively on Sapphire” bounty during ETHDam 2024’s hackathon. This three-day hackathon called builders and enthusiasts to explore blockchain’s privacy features, with a special bounty for building with Oasis Sapphire’s confidential EVM, to showcase the different types of privacy-preserving dApps that can be built in an EVM environment. With a substantial prize pool of $10,000 and an extra $2,000 bounty toward AI development on Sapphire, the competition worked to recognize and reward six projects that demonstrated innovation, creativity and confidentiality while leveraging the features of Sapphire.

During the hackathon, Community Lead Mihnea Stefanescu interviewed hackers to get their thoughts on Sapphire, what it was like to build on the industry’s first confidential EVM, and more. Check them out here and here!

Bounty Overview

Hackers were challenged to develop working software applications that addressed real-world problems through the utilization of Oasis Sapphire’s unique EVM-compatible confidentiality . The criteria for qualifying entries included  open-source code, demonstration of project functionality on Sapphire and integration of confidential features , among others. Furthermore, judges evaluated projects based on criteria such as implementation quality, potential impact, confidentiality, innovation, user experience, and originality. An additional AI bounty was launched to challenge hackers to combine the confidential features of Sapphire with AI.

Winners’ Showcase

The winners of the Build Natively on Sapphire bounty brought forth impressive innovation on Sapphire’s unique customizable confidentiality integration, pushing the boundaries of Sapphire’s capabilities. Among the winning dApps were an array of other exciting and innovative projects, ideas, and talents. Let’s explore the top six projects and what kind of technology their dApps can bring to Sapphire.


OasisGuard, winner of a $4,000 bounty, won the highest bounty for its innovative browser extension designed to safeguard passwords within a confidential smart contract. Leveraging Sapphire’s Confidential EVM, OasisGuard ensures robust password security, allowing for secure sharing of passwords via Semaphore. Passwords are then accessed via the user’s unique Passkey (Webauthn) and authenticated through r1 curve signatures on Oasis


0x2FA, winner of a $2,500 bounty, introduces a decentralized solution for two-factor authentication, addressing the critical need for enhanced security in Web2 and Web3 applications. By leveraging Oasis, Bandada and Near, 0x2FA brings a privacy-based authentication mechanism to Sapphire, promising heightened security for users across various platforms.


PrivAds, winner of a $2,000 bounty, tackles privacy concerns in advertising by ensuring the encryption and anonymity of user data throughout the ad-serving process. Employing a combination of smart contracts, decentralized storage solutions, and machine learning models, PrivAds sets a new standard for privacy-preserving advertising practices in the blockchain space.


B-Hook, winner of a $1,500 bounty, introduces a platform for interactive content creation, offering creators a new way to engage with their audience and monetize their work. By enabling collaborative content creation and feedback mechanisms, B-Hook brings more interactive experience with privacy-enabled crowd-funding for sponsorships with public previews and private access to specific users

Blockchain of Things

Blockchain of Things, winner of a $1,000 bounty, presents a community-driven ecosystem aimed at simplifying the process of creating an oracle. With features such as anonymous transactions, incentivized participation, and broad compatibility with IoT devices, users can then subscribe to data feeds provided by creators from iOT devices.


Blacksea, winner of a $1,000 bounty, introduces a cross-chain dark pool order book for added protection for founders, whales, and institutional investors. By leveraging Sapphire’s privacy-preserving properties, Blacksea ensures confidential order processing and protects large orders from front-running.

The Build Natively on Sapphire bounty winners and participants showcased the potential of Oasis Sapphire’s confidential EVM technology in driving innovation and privacy-enhancing solutions within the blockchain and AI ecosystem. Congratulations to all the winners and participants whose efforts are shaping the future of dApps on Sapphire, and beyond.

To learn more about the Build Natively on Sapphire bounty winners and a host of other dApps utilizing the power of Oasis Smart Privacy — check out the Oasis Playground.