File Encrypt / Decrypt
This free file encryption tool locks any file with a password using AES-256, and decrypts your .gwtenc files back to the original. Both the file and the password stay on your device — nothing is ever uploaded.
AES-256-GCM with a PBKDF2 key (250,000 iterations, SHA-256). Everything runs in your browser — the file and password never leave your device. There is no password recovery: lose the password and the file is unrecoverable.
How to use File Encrypt / Decrypt
- 1 Choose Encrypt to lock a file, or Decrypt to unlock a .gwtenc file.
- 2 Drop your file onto the box or click to browse for it.
- 3 Type a strong password (8+ characters, a passphrase is best).
- 4 Click Encrypt file or Decrypt file, then download the result.
Frequently asked questions
Is my file or password uploaded anywhere?
No. Encryption and decryption run entirely in your browser using the Web Crypto API. The file and password never leave your device.
What encryption does it use?
AES-256-GCM, with the key derived from your password via PBKDF2 using 250,000 SHA-256 iterations — strong, standard, browser-native cryptography.
What happens if I forget the password?
There is no recovery. Without the exact password the file cannot be decrypted, so store it somewhere safe before you close the tab.
What file do I get, and does it work offline?
Encrypting produces a .gwtenc file to keep; decrypting restores the original. As a PWA the tool keeps working offline once the page has loaded.