File encryptor — password-protect a file
Encrypt or decrypt a file with a password using AES-256-GCM. It runs entirely in your browser using Web Crypto (0 uploads, works offline) — the file and password never leave your device.
How to use it
- Choose Encrypt or Decrypt and enter a password.
- Select the file.
- Download the result.
FAQ
How do I password-protect a file for free?
Choose Encrypt, enter a password and select the file; this page encrypts it with AES-256-GCM (key derived from your password via PBKDF2) and gives you an encrypted file — on your device with no upload.
Is my file or password uploaded anywhere?
No. Everything happens in your browser using Web Crypto and nothing is transmitted or stored, which you can verify by turning off your Wi-Fi. Encrypting on a server would mean trusting it with your file.
How do I decrypt later?
Choose Decrypt, enter the same password and select the .enc file; the original is restored. There is no password recovery — the password is the only key.
What algorithm is used?
AES-256-GCM with a per-file random salt and nonce, and PBKDF2 key derivation, the same as the text AES tool.
Limits
Best for small-to-medium files since everything is held in the browser tab; it is not a whole-disk or streaming encryptor.
Related
The AES text tool encrypts text; the file checksum verifier checks integrity.
Bookmark this page (Ctrl+D, or ⌘D on Mac) or install the app — it works offline the next time you need it.