Nostreum

Nostreum: Bridging Ethereum & Nostr Through Cryptographic Identity Linking

Nostreum introduces the first on-chain verification system that links different cryptographic protocols, creating a cryptographically provable bridge between ECDSA signatures used by Ethereum and Schnorr signatures employed by Nostr through smart contract verification.

Core Innovation

The fundamental breakthrough lies in a Scaffold-ETH extension that enables on-chain verification linking an Ethereum private key (ECDSA) with a Nostr private key (Schnorr). This creates a mathematical bridge between Ethereum's financial ecosystem and Nostr's social network, allowing one identity to operate across both platforms with cryptographic proof.

Enhanced Social Platform

Nostreum functions as a full-featured Nostr client with complete social networking capabilities including feeds, following, profile discovery, and decentralized publishing. The key innovation adds cross-platform features: ETH verification badges display linked Ethereum addresses on Nostr profiles, while cross-platform search allows finding users by their Ethereum address, giving financial accounts social identities.

Unlocked Possibilities

The cryptographic bridge enables bidirectional value flow. Users can leverage social reputation from Nostr to access financial opportunities on Ethereum, while displaying on-chain achievements like NFTs and DeFi success as social credibility. This particularly benefits activists who can receive Ethereum funding while maintaining censorship-resistant Nostr communication, and creators who can monetize through Ethereum while building audiences on Nostr.

Technical Implementation

The system uses Scaffold-ETH framework extended with Nostr protocol integration. Users connect their Ethereum wallet, generate cryptographic proof linking their keys, then smart contracts validate and store the identity link on-chain. This enables enhanced cross-platform features across both ecosystems.

Current Status and Future

Live demos showcase wallet linking, social feeds with ETH badges, cross-platform user search, and cryptographic proof verification. Future development includes NFT gallery integration, DeFi activity badges, multi-chain support, and reputation-based financial services. Notably, Schnorr signatures also function as Bitcoin addresses, making this potentially a three-way Bitcoin-Nostr-Ethereum bridge.

Getting Started

Requirements include Node.js 18+, Ethereum wallet, and Git. Install by cloning from https://github.com/VincenzoImp/nostreum.git, then run `yarn install`, `yarn chain`, `yarn deploy`, and `yarn start`. Access at localhost:3000 to connect wallet and explore features.

Live demos available on Base Sepolia and Avalanche Fuji. Full source code and presentation available on GitHub.

Nostreum builds the foundation for unified decentralized identity, creating new possibilities for leveraging digital presence across multiple blockchain ecosystems.