Drag-and-Drop File Encryptor

Password-protect a file with real AES-256 encryption, entirely in your browser — nothing is ever uploaded, and the file never leaves your device.

The fastest way to encrypt a file online without actually sending it anywhere: drop in any file, set a password, and get back an encrypted copy that's safe to email or hand off — decrypt it the same way, with the same password. Encryption uses the browser's own built-in AES-256-GCM cipher, with your password stretched through 600,000 rounds of PBKDF2 before it ever touches the actual encryption key. This is one static HTML file with no server, no account, and no network requests of any kind — verify that yourself by reading the page's own source, or just by opening it with your Wi-Fi off. One-time purchase, works offline forever.

What it does

What it does: Encrypts a single file with a password using the Web Crypto API's native AES-256-GCM cipher. Your password is never used directly as the key — it's run through PBKDF2 (600,000 iterations of SHA-256, the current OWASP-recommended minimum) with a random salt to derive the actual 256-bit encryption key, and a random IV is generated per file. The salt, IV, iteration count, and original filename are stored in a small plain header at the front of the output file, so decrypting only ever needs the password — nothing else to remember or keep track of. Decrypting reverses the process and, thanks to AES-GCM's built-in authentication tag, either restores the file byte-for-byte or fails with a clear, honest error — it never silently hands back corrupted garbage.

Who it's for: Someone who needs to send a genuinely sensitive file to another person over an ordinary, non-secure channel — email, a shared drive, a messaging app — and wants real protection in transit and at rest, without installing anything or trusting a third-party server with the file.

Example scenario: A freelancer finishes a signed tax document and needs to email it to their accountant. Email itself isn't encrypted end-to-end, and the document has a Social Security number on it. They drop the PDF into this tool, set a password, and attach the resulting .enc file instead of the original. They call the accountant and read the password over the phone (or send it through a different channel than the email itself) — a genuinely different, much safer thing than mailing the plain PDF and hoping for the best.

What it explicitly does not do:

• Does not recover, reset, or store your password anywhere. If you forget it, the file is permanently unreadable — by you or anyone else. That is not a missing feature; it is what makes the encryption real. See the FAQ.
• Does not encrypt multiple files or whole folders at once — one file in, one encrypted file out. Zip a folder first with your OS's built-in tools if you need to encrypt several files as a unit.
• Does not manage, share, or transmit passwords for you. You still need a separate, safe way to get the password to the recipient (a phone call, a different app, in person) — this tool only handles the encryption itself.
• Does not stream large files in chunks — the whole file is read into memory before encrypting. Tested comfortably up to 500MB in well under a second (see Performance below); a genuinely enormous file (many gigabytes) is an untested case and may hit browser memory limits.
• Does not add a second, independent layer of protection like a hardware key or two-factor unlock — this is standard, single-password, symmetric encryption, the same category as a 7-Zip AES-256 archive or an encrypted disk image, not a replacement for a full secrets manager.

Features

• Encrypts any single file with AES-256-GCM, the browser's own built-in, audited cipher — no custom cryptography written for this tool
• Derives the encryption key from your password with PBKDF2 at 600,000 iterations of SHA-256, the current OWASP-recommended minimum, so brute-forcing the password is genuinely expensive
• Detects a wrong password instantly and tells you so clearly, instead of producing corrupted-looking output — AES-GCM's built-in authentication tag makes this possible
• Stores the salt, IV, and original filename inside the encrypted file itself, so decrypting only ever needs the password — nothing else to write down or lose
• Password-strength feedback and a prominent, unmissable warning that there is no password recovery, shown before you can encrypt anything
• Runs entirely offline — no network requests, no analytics, nothing uploaded, verifiable by reading the page's own plain, unminified source

Browser support

Method note on "automated testing": beyond opening each real installed browser app and visually confirming the page renders, the functional flow was exercised end-to-end using Playwright driving each engine's own real Chromium/WebKit/Gecko binary — encrypting a real file, downloading the actual output, hashing both the original and the round-tripped decrypted file with SHA-256 to confirm an exact byte-for-byte match, and separately confirming both "wrong password" and "not an encrypted file" produce the intended clean error messages rather than a crash, a hang, or silent garbage output. This is the same code actually run, in three real engines, not code read and assumed correct.

FAQ

Does my file get uploaded anywhere?
No. The entire tool is one static HTML file with no server component and no network calls of any kind. Encryption and decryption both happen locally in your browser tab using the Web Crypto API. You can open it with your Wi-Fi off, or read the page's own source — it isn't minified or obfuscated — to confirm there's nothing that sends data anywhere.

Does this work on my iPhone/iPad?
It's expected to, since iOS Safari shares desktop Safari's engine and the same Web Crypto API already confirmed working on desktop Safari — but this hasn't been tested on a physical iOS device, so it isn't claimed as verified. If you try it on iOS and hit an issue, that's useful to know.

What happens if I forget the password?
The file is permanently, unrecoverably unreadable. This tool has no password reset, no backdoor, no "contact support to recover your file" — that absence is not a missing feature, it's the actual security property that makes the encryption real. Write your password down somewhere safe before you close the tab.

Is this "real" encryption, or security theater?
It's real. The cipher is AES-256-GCM and the key derivation is PBKDF2-HMAC-SHA256 at 600,000 iterations — both implemented by your browser's own built-in, independently audited Web Crypto API, not custom code written for this tool. That's the same cryptographic category as a 7-Zip AES-256 archive or a macOS encrypted disk image, using a standard, well-reviewed browser API rather than a bespoke implementation.

Can I use this for client or commercial work?
Yes — personal and commercial use are both fine.

Is there a subscription?
No. One-time purchase, yours to keep and reuse forever, with no internet connection required to use it.

What happens to my file if I lose the download?
Nothing is stored by the tool anywhere — it holds nothing in memory once you reload the page or close the tab. If you lose an encrypted file you downloaded, you'd need to encrypt the original again (assuming you still have it); there's no separate copy kept anywhere by this tool.