File Encryption
Free online file encryption. Password-protect any file up to 512 MB with AES-256-GCM and Argon2id key derivation. Runs entirely in your browser — no upload, no install.
How does this tool encrypt my file?
It derives a 256-bit key from your password with Argon2id (64 MB of memory, 3 passes, a fresh random 16-byte salt) and then encrypts the whole file with AES-256-GCM using a new random 12-byte nonce. Both run inside your browser via WebAssembly and the WebCrypto API.
Does my file or password get uploaded anywhere?
No. Everything happens on your device inside the browser tab. The file is read with the File API, encrypted in memory and handed back to you as a download. There is no server, no account and no tracking.
What is inside the .enc file?
A small header (the LTKENC1 signature, a format version, the random salt, the nonce and your original file name) followed by the encrypted bytes. The header holds no secrets — all security rests on your password.
I forgot my password. Can my file be recovered?
No. There is no backdoor, key escrow or reset. AES-256-GCM driven by an Argon2id key is practically unbreakable, so a lost password means the data is lost. Keep your password in a password manager.
What is the maximum file size?
Files up to 512 MB can be encrypted in one pass. AES-GCM processes the data as one block in memory, so anything larger is declined to keep the tab stable and responsive.
Why does a "Deriving key" step run before encryption?
That is Argon2id deliberately spending memory and time (64 MB, 3 passes) to make brute-forcing your password extremely expensive. The short wait is a security feature, not a slow computer.
Can I decrypt the .enc file on another computer or later?
Yes. The .enc file is self-contained: open this same tool on any device — it even works offline after the first load — enter the same password and the original file with its original name comes back.
Which file types can I encrypt?
Any kind: photos, PDFs, archives, spreadsheets, videos, databases. The tool treats the file as raw bytes and restores the original file name automatically on decryption.
How is this better than a password-protected ZIP?
Legacy ZIP password protection often uses weak or outdated ciphers. Here you get a modern AEAD cipher (AES-GCM) that also detects tampering, plus a memory-hard key derivation designed specifically for passwords.
How to Use File Encryption
This tool locks any file behind a password using AES-256-GCM, with the key derived by Argon2id from your password alone. The file is read, encrypted and written back entirely on your device — nothing is uploaded, and there is no account. The result is a single portable .enc file that decrypts back to the exact original bytes on any device with this tool.
- Drop any file onto the upload box or click it to browse — files up to 512 MB are supported.
- Type a strong password and watch the strength bar update; aim for Good or Strong.
- Repeat the password in the confirm field — the mismatch hint disappears when both entries match.
- Press "Encrypt & Download". The "Deriving key" step is Argon2id hardening your password, then the .enc file downloads automatically.
- To recover the original, switch to the Decrypt tab, drop the .enc file and enter the same password — the file returns with its original name.
Store the password in a password manager before you close the tab. There is no recovery path: without the exact password, nobody — including this tool — can open the encrypted file.
Related Tools
- Text Encryption Secure text encryption and decryption with AES-GCM/AES-CBC. Password-based, browser-only processing, no data leaves your device.
- PGP Encryption Encrypt and decrypt PGP messages online, generate OpenPGP key pairs and inspect key fingerprints. Powered by openpgp.js and running entirely in your browser - keys and messages never leave your device.
- Hash Generator Generate MD5, SHA-1, SHA-256, SHA-512 hashes from text instantly in your browser
- File Hash Checker Calculate and verify MD5, SHA-1, SHA-256, SHA-512 file hashes locally
- Password Generator Generate strong, secure random passwords instantly. Customize length, characters, and create bulk passwords online — 100% browser-based, no data leaves your device.
- Bcrypt Generator Generate and verify bcrypt password hashes online. Adjustable cost factor, built-in salt, real-time hash preview. All processing runs locally in your browser — no data sent to any server.
- PDF Unlock Remove password protection from PDF files instantly in your browser. Includes smart brute-force password recovery.
- Protect PDF Add password protection to PDF files online for free. Encrypt PDF documents with AES-256 encryption to prevent unauthorized access. 100% browser-based, no upload required.