Secure Enclave module for node.js and Electron

This module provides support for Secure Enclave operations in Electron apps.

Demo

Download a working app here: https://github.com/antelle/node-secure-enclave/releases/latest

That's what you're expected to see:

And on your Touch Bar:

Features

• works with Electron
• hardware encryption, private keys don't leak
• shows the password prompt in case of "lockout"
• no dependencies, no bloatware
• ≈50k of native code, no javascript

Requirements

Runtime:

• macOS: Secure Enclave doesn't exist on other OS
• limited to MacBooks with a Touch Bar

Development:

• the app must be codesigned
• provisioning profile, see below
• Xcode with command-line tools
• clang-format
• it's strongly recommended to lock down your Electron

Installation

npm i secure-enclave

API

This snippet shows the basic usage:

const SecureEnclave = require('secure-enclave');

if (!SecureEnclave.isSupported) {
    // Secure Enclave cannot be used on this Mac
}

// more about this tag: https://developer.apple.com/documentation/security/certificate_key_and_trust_services/keys/generating_new_cryptographic_keys#2863927
const keyTag = 'com.your-team.app.this-key';

const key = await SecureEnclave.findKeyPair({ keyTag });
if (key) {
    // key exists, you can use key.publicKey (Buffer)
    const data = Buffer.from('something');
    // these operations return Buffer too
    data = await SecureEnclave.encrypt({ keyTag, data });
    data = await SecureEnclave.decrypt({ keyTag, data,
        // some human-readable text for your users
        touchIdPrompt: 'decrypt data' });
    
    // if you don't need the key anymore
    await SecureEnclave.deleteKeyPair({ keyTag });
} else {
    // key doesn't exist yet
    await SecureEnclave.createKeyPair({ keyTag });
}

Inspect node-secure-enclave.d.ts for detailed information about the API.

Library development

To test the app, you need a provisioning profile. Generate it on Apple Developer website and save it as conf/test-app.provisionprofile.

Once you have your provisioning profile and certificates installed, put your app and team id to conf/test-app.entitlements.plist, otherwise it won't build.

Build everything and run the test app:

npm start

Generate an Xcode project for editing C++ and Objective C:

npm run generate-xcode-project

Run the test app:

npm run test-app

Run unpackaged app to iterate on UI faster (API won't work there):

npm run test-app-unpackaged

Run unit tests:

npm test

Reformat all C++ and JavaScript:

npm run format

Evil Electron features

Since you're going to store secrets in Secure Enclave, it's essential that malicious apps can't run code under your app's identity. I have a module for you that disables evil features in Electron: electron-evil-feature-patcher, this will remove all debugging flags in your app.

Otherwise, anyone can launch your app with --inspect-brk and enjoy your secrets from Secure Enclave, which defeats the purpose of code signing and provisioning.

Troubleshooting

There are several common errors:

SecKeyCreateRandomKey: A required entitlement isn't present.

If you got this, it means your app is not codesigned properly, in particular, a provisioning profile may be missing or bad in some form. More info in this thread.

To validate if everything is ok, run

codesign -d --entitlements :- your-app.app

and make sure the output contains com.apple.application-identifier and com.apple.developer.team-identifier entitlements.

References

• https://developer.apple.com/documentation/security/certificate_key_and_trust_services/keys/storing_keys_in_the_secure_enclave
• https://github.com/atom/node-keytar/blob/master/src/keytar_mac.cc
• https://medium.com/@alx.gridnev/ios-keychain-using-secure-enclave-stored-keys-8f7c81227f4
• https://gist.github.com/microshine/8b511824d440d4792cc5114e8b92a35e
• https://developer.apple.com/forums/thread/107586

License

MIT