Crypto Box

Encrypt and decrypt text with Web Crypto (AES-GCM) locally in LocalKit. Keep notes private in your browser—ciphertext and keys are not uploaded for computation.

Interactive controls load with JavaScript. Processing stays in your browser—nothing is uploaded.

Loading tool…

How to use

  1. Open Crypto Box — Load the tool.
  2. Enter text & password — Keep secrets off shared screens.
  3. Encrypt or decrypt — Run the selected action.
  4. Copy ciphertext — Store outputs safely.

Limits

Requires JavaScript. Extremely large inputs may slow the browser tab. Results depend on your browser APIs; there is no server-side processing quota because nothing is uploaded.

When to use

When you want a quick, free utility without creating an account or sending content to an online converter.

When not to use

When you need server-side integration, batch automation at scale, or certified compliance tooling.

Privacy note

Tool inputs are processed in your browser only. Theme, language and favorites may use localStorage; hosting may keep standard access logs (IP, UA, URL) without tool payloads.

FAQ（5）

Algorithm?

AES-GCM via Web Crypto with a password-derived key (see on-page options).

Is this Signal/PGP?

No—convenient local encryption, not a full messaging suite.

Lost password?

Ciphertext cannot be recovered without the password.

Uploaded?

Never—keys and plaintext stay on-device.

Output format?

Typically Base64 JSON packing IV/ciphertext for easy copy.