Encrypt or decrypt any file with a passphrase using AES-256-GCM and PBKDF2 key derivation, entirely in your browser. Nothing is uploaded.
Most “encrypt a file online” tools quietly upload the file to a server before doing anything to it, which defeats the point if the file is sensitive enough to need encrypting in the first place. The AES File Encryptor runs the whole job inside the tab you’re looking at: key derivation, encryption, and the download, using the same Web Crypto API your browser already ships with.
Reach for it when you’re handing a spreadsheet of client data to a contractor over email, backing up a database dump onto a USB drive you don’t fully trust, or storing a document somewhere you don’t control the access logs. Pick a mode, drop in a file, add a passphrase, and the browser does the rest.
.enc extension switches the mode for you automatically.crypto.getRandomValues. Click the eye icon if you want to check what’s actually in the field..enc appended when encrypting or stripped back off when decrypting.The 100 MB ceiling is enforced before anything touches the Web Crypto API, so an oversized file fails immediately with its exact size quoted in the error rather than freezing the tab. Encryption itself is fast: AES-GCM processes tens of megabytes in well under a second on a modern laptop. Deriving the key is deliberately not fast. PBKDF2 runs 250,000 rounds of SHA-256 over your passphrase, which is what makes guessing it expensive for anyone who only has the file. Every output carries a fixed 32-byte header in front of the ciphertext: a 4-byte marker, a 16-byte salt, and a 12-byte IV.
If you forget the passphrase, the file is gone. There’s no reset link, no recovery key, and no account tied to it, because none of that infrastructure exists here. Typing the wrong passphrase doesn’t corrupt anything either: the decrypt attempt runs, the GCM authentication tag fails to verify, and you get “Decryption failed — wrong passphrase, or this file has been modified since it was encrypted.” instead of garbled output. A passphrase under 8 characters triggers a separate warning, but nothing stops you from using it anyway; treat that as a nudge, not a gate. For encrypting many files under one shared key, or for the asymmetric case where the person decrypting never sees your secret, this single-passphrase tool is the wrong shape for the job.
Drop a file here, or click to browse
Any file type · max 100 MB · encrypted entirely in your browser
How it works
Add a file and a passphrase, then encrypt. Behind the scenes, the passphrase runs through PBKDF2 (250,000 rounds, SHA-256) with a random salt to derive a 256-bit AES-GCM key, which encrypts the file with a random 12-byte IV. Both the salt and IV travel in a 32-byte header on the front of the .enc file, so you only need to remember the passphrase — nothing else is uploaded or stored anywhere.