AutistMask

AutistMask is a GPL-licensed JavaScript browser extension by @sneak that provides a minimal Ethereum wallet for Chrome and Firefox. It manages HD wallets derived from BIP-39 seed phrases and supports sending and receiving ETH and ERC-20 tokens, as well as web3 site connection and authentication via the EIP-1193 provider API.

Getting Started

git clone https://git.eeqj.de/sneak/autistmask.git
cd autistmask
yarn install
make build

Load the extension:

• Chrome: Navigate to chrome://extensions/, enable "Developer mode", click "Load unpacked", and select the dist/chrome/ directory.
• Firefox: Navigate to about:debugging#/runtime/this-firefox, click "Load Temporary Add-on", and select dist/firefox/manifest.json.

Rationale

MetaMask has become bloated with swap UIs, portfolio dashboards, analytics, tracking, and advertisements. It is no longer a simple wallet. Most alternatives (Rabby, Rainbow, etc.) only support Chromium browsers, leaving Firefox users without a usable option.

AutistMask exists to provide the absolute minimum viable Ethereum wallet experience: manage seed phrases, derive HD addresses, send and receive ETH and ERC-20 tokens, and connect to web3 sites. Nothing else. No swaps (that's what the web is for), no analytics, no tracking, no ads, no portfolio views, no NFT galleries. Just a wallet.

Design

AutistMask is a browser extension targeting both Chrome (Manifest V3) and Firefox (Manifest V2/V3 as supported). The codebase is shared between both targets with platform-specific manifest files and a build step that produces separate output directories.

Architecture

src/
  background/       — service worker / background script
    index.js        — extension lifecycle, message routing
    wallet.js       — wallet management (create, import, derive)
    provider.js     — EIP-1193 JSON-RPC provider implementation
    transaction.js  — transaction construction and signing
  popup/            — popup UI (the main wallet interface)
    index.html
    index.js
    components/     — UI components (account list, send form, etc.)
    styles/         — CSS
  content/          — content script injected into web pages
    index.js        — injects the provider into page context
    inpage.js       — the window.ethereum provider object
  shared/           — shared utilities
    crypto.js       — BIP-39 mnemonic, HD key derivation, signing
    storage.js      — encrypted storage abstraction
    constants.js    — chain IDs, default RPC endpoints, ERC-20 ABI
    rpc.js          — JSON-RPC client for Ethereum nodes
manifest/
  chrome.json       — Manifest V3 for Chrome
  firefox.json      — Manifest V2/V3 for Firefox

Key Decisions

• No framework: The popup UI is vanilla JS and HTML. The extension is small enough that a framework adds unnecessary complexity and attack surface.
• Encrypted storage: Seed phrases are encrypted with a user-provided password using AES-256-GCM before being stored in the extension's local storage. The encryption key is derived from the password using PBKDF2 with a high iteration count.
• BIP-39 / BIP-44: Standard mnemonic generation and HD key derivation (m/44'/60'/0'/0/n) for Ethereum address compatibility.
• EIP-1193 provider: The content script injects a window.ethereum object that implements the EIP-1193 provider interface, enabling web3 site connectivity.
• Minimal RPC: The extension communicates with Ethereum nodes via JSON-RPC. The default endpoint is configurable. No Infura dependency — users can point it at any Ethereum JSON-RPC endpoint.
• No external services: No analytics, no tracking, no telemetry, no ads, no phishing lists, no token price feeds. The extension only talks to the configured Ethereum RPC endpoint.

Supported Functionality

• Create new wallet from generated BIP-39 mnemonic
• Import wallet from existing BIP-39 mnemonic
• Derive multiple HD addresses per wallet (m/44'/60'/0'/0/n)
• View ETH balance
• View ERC-20 token balances (user adds token by contract address)
• Send ETH to an address
• Send ERC-20 tokens to an address
• Receive ETH/tokens (display address + copy to clipboard)
• Connect to web3 sites (EIP-1193 eth_requestAccounts)
• Sign transactions requested by connected sites
• Sign messages (personal_sign, eth_sign)
• Switch between wallets/accounts
• Lock/unlock with password
• Configurable RPC endpoint

Non-Goals

• Token swaps (use a DEX in the browser)
• Portfolio/price tracking
• NFT display or management
• Multi-chain support (Ethereum mainnet only, for now)
• Analytics, telemetry, or tracking of any kind
• Advertisements or promotions
• Phishing detection (use your brain)
• Hardware wallet support (maybe later)

TODO

• Set up build system (webpack/esbuild) for Chrome and Firefox targets
• Implement BIP-39 mnemonic generation and validation
• Implement BIP-32/BIP-44 HD key derivation for Ethereum
• Implement encrypted storage for seed phrases
• Build popup UI: lock screen, account list, send/receive views
• Implement background wallet manager
• Implement EIP-1193 provider and content script injection
• Implement ETH send/receive
• Implement ERC-20 token management (add by contract, view balance, send)
• Implement site connection approval flow
• Implement transaction signing approval flow
• Implement message signing (personal_sign, eth_sign)
• Add configurable RPC endpoint
• Test on Chrome and Firefox
• Write tests for crypto operations
• Write tests for transaction construction
• Security audit of key management

License

GPL-3.0. See LICENSE.

Author

@sneak