Getting started

1 · Encrypt a file in the browser

1. Open arc-shield.xyz/app.
2. Pick a key source: connect a wallet and sign, or generate/load a key file with a passphrase.
3. Drop a file and click Encrypt → .arshield.
4. Download the sealed envelope and its Quantum Seal. Nothing was uploaded.

2 · Open a file

1. Drop the .arshield envelope into the app.
2. Unlock the same key source (same wallet signature or same key file).
3. Click Decrypt — the ML-DSA-65 signature is verified before a single byte is decrypted.

3 · Back up your keys

A wallet-derived keypair can be reproduced from the wallet signature alone, so the working backup of a wallet path is the wallet itself. If you would rather not depend on the wallet curve, generate a passphrase-protected key file from the key-source screen instead: it holds random keys that never touch your wallet's signature, and it opens your files on its own. Lose both the wallet and the key file, and the files are unrecoverable — that is the point.

4 · Use it from an agent

Install the MCP server and give your agent the same wallet signature or key file: