Shell dApp Prototype

Live demo: https://shelldappprototype.vercel.app/

This project was submitted to the Logos Lambda Prize and won. The winning proposal is linked in that PR.

A web dApp that integrates with the Shell hardware wallet entirely via QR codes — no browser extension, no USB, no Bluetooth. Everything goes through the camera.

What it does

1. Connect — scan Shell's QR code to import your extended public keys
2. Addresses — displays your derived addresses across all supported derivation paths
3. Sign — type a message, tap Sign, scan the animated QR with Shell, then scan Shell's response to receive the signature

Supported key types:

Key	Path	Address format
EVM / Ethereum	m/44'/60'/0'/0/0	EIP-55 checksummed
Bitcoin Legacy	m/44'/0'/0'/0/0	P2PKH (1...)
Bitcoin Nested SegWit	m/49'/0'/0'/0/0	P2SH-P2WPKH (3...)
Bitcoin Native SegWit	m/84'/0'/0'/0/0	bech32 (bc1q...)

Getting started

npm install
npm run dev

Open the local URL in a browser that has camera access. On desktop, allow camera permission when prompted.

Other commands

npm test          # run tests (vitest)
npm run build     # production build
npm run lint      # ESLint
npx prettier --write "src/**/*.{ts,tsx,css}"

How it works

Shell speaks ERC-4527 — a QR-based airgapped signer protocol built on Uniform Resources (UR) and CBOR. The dApp:

• Decodes ur:crypto-hdkey and ur:crypto-account QR codes (including animated multi-part QRs) to extract account-level extended public keys
• Derives addresses locally using @scure/bip32
• Encodes ur:eth-sign-request and ur:btc-sign-request payloads as animated QR codes when needed so longer messages still round-trip
• Verifies scanned Bitcoin signatures against the signed address and message with bip322-js
• Decodes ur:eth-signature and ur:btc-signature responses from Shell

See docs/integration-guide.md for the full developer integration guide.

Project structure

src/
  lib/                  # framework-agnostic protocol library
    parseXpub.ts        # UR / base58 xpub → ParsedXpub[]
    deriveKeys.ts       # derive addresses from parsed keys
    ethereumAddress.ts  # pubkey → EIP-55 address
    bitcoinAddress.ts   # pubkey → P2PKH / P2WPKH / P2SH-P2WPKH
    ethSignRequest.ts   # build ur:eth-sign-request
    ethSignature.ts     # parse ur:eth-signature
    btcSignRequest.ts   # build ur:btc-sign-request
    btcSignature.ts     # parse ur:btc-signature
    cbor.ts             # minimal CBOR encoder with tag support
    react/              # React hook + QR scanner component
  components/           # app UI
  test/                 # Vitest tests
docs/
  integration-guide.md  # developer guide

Tech stack

• React 19 + TypeScript + Vite
• @ngraveio/bc-ur — UR encoding/decoding
• @scure/bip32 — HD key derivation
• @noble/hashes — SHA-256, Keccak-256, RIPEMD-160
• @scure/base — base58check, bech32
• bip322-js — Bitcoin message verification
• cborg — CBOR decoding
• jsqr — camera QR decoding
• qrcode — QR code rendering
• Vitest — tests

License

Apache-2.0