PolkaSafe

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  PolkaSafe Web3 login with MetaMask wallet connection for secure messaging"

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  Encrypted message inbox with one-click decryption using private keys

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  create new message, image upload and blockchain encryption

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  Decrypted message view showing end-to-end encrypted content"

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  Sent messages interface with delivery status and encryption history

Inspiration

Privacy is a fundamental right, not a privilege. We built PolkaSafe because centralized messaging platforms can censor, monitor, and control user communications. Our vision: messaging that users truly own - no servers, no surveillance, no single points of failure.

What it does

PolkaSafe Enables

• Secure Messaging – Encrypted text messages stored on-chain; only recipients can decrypt
  
• Image Sharing – Encrypted image uploads through IPFS integration
  
• Self-Custody – Users control private keys via MetaMask; zero third-party access
  
• Censorship Resistance – On-chain messages cannot be deleted or blocked by authorities
  
• Cross-Chain Ready – Built on the Polkadot ecosystem for multi-blockchain compatibility
  
• Zero Servers – Fully decentralized; no central servers to shut down or compromise
  
• Professional Use – Secure document exchange for lawyers, doctors, journalists, and activists
  

Key Features:

• 500KB message capacity per transaction
• Client-side encryption (ECIES)
• Public key registry for secure communication
• Dual storage system (IPFS + Base64 fallback)
• Web3 authentication via wallet connection

How we built it

Frontend Layer:

• Next.js 15 + React 19 + TypeScript application
• MetaMask wallet integration
• User interface for messaging

Blockchain Layer:

• Solidity smart contract on Moonbase Alpha testnet
• Message storage and retrieval functions
• User public key registry
• Event emission for message tracking

Storage Layer:

• IPFS for decentralized image storage
• Base64 fallback storage in smart contract
• Encrypted message content

Data Flow Arrows showing:

1. User → Next.js Frontend → MetaMask (encryption)
2. MetaMask → Smart Contract → Moonbase Alpha (storage)
3. Images → IPFS → Base64 fallback
4. Blockchain events → Frontend (real-time updates)
5. Recipients → MetaMask (decryption) → Readable messages

Tech Stack

• Polkadot – blockchain interoperability
  
• Web3.js / Polkadot.js – wallet connection
  
• Client-side cryptography – security without compromises
  
• Frontend: Next.js 15, React 19, TypeScript, Tailwind CSS
  
• Storage: IPFS for images, on-chain for messages (500KB capacity)

Challenges we ran into

• Gas Optimization – Initial contract exceeded gas limits; redesigned storage for efficient 500KB message handling
  
• Encryption UX – Balanced strong security with smooth user experience using MetaMask’s native encryption
  
• IPFS Reliability – Node inconsistency issues solved via dual-storage architecture with Base64 fallback
  
• Web3 Onboarding – Made blockchain messaging accessible even for non-crypto users
  

Accomplishments that we're proud of

• True Decentralization – Zero centralized components; fully Web3 architecture
  
• Seamless UX – A Web3 messaging experience that feels like Web2
  
• 500KB Message Capacity – Optimized smart contract for large content storage
  
• Multi-format Support – Encrypted text messages + image uploads
  
• Production Ready – Deployed and tested on Moonbase Alpha testnet
  

What we learned

• Smart Contract Optimization – Balancing gas efficiency with rich functionality
  
• Client-side Encryption – Implementing ECIES without sacrificing usability
  
• IPFS Integration – Addressing decentralized storage reliability challenges
  
• Polkadot Ecosystem – Unlocking the benefits of blockchain interoperability
  
• Web3 Philosophy – True ownership means removing all centralized dependencies

What's next for PolkaSafe

• Mobile apps (iOS & Android)
  
• Enhanced file type support (documents, videos)
  

Long-term Vision:

• DAO governance for community-driven decisions
  
• Zero-knowledge proofs for enhanced privacy
  
• Enterprise features for organizations
  
• Cross-platform desktop applications
  

Contract: 0xE48b7351ea11A366509203C508E0222D3B428a34 (Moonbase Alpha)

Built With

• ecies
• ethers.js
• hardhat
• ipfs
• metamask
• moonbase
• next.js
• openzeppelin
• solidity