Encrypted in this tab AES-256-GCM · WebCrypto

# Cloak anything.
Reveal nothing.

CloakDrop encrypts your files in this tab with AES-256-GCM. The key is generated here, stays here, and rides inside the link — never on a server. Today it encrypts and stores; it does not yet send. A link opens only in the browser that made it.

Cloak a file
How it's secured

A CloakDrop link is plain text, so it survives any channel you already use

Not yet, though: in this build a link only opens in the browser that made it. Sending one to someone else shows them an empty page. The relay that will carry drops between devices is being built — what works today.

The drop

## Cloak your files

Cloak files Open a link
Open a CloakDrop link

Paste it here — the key after the # stays in your browser and unlocks the files locally. In this build a link opens only in the browser that created it.

That doesn't look like a CloakDrop link — it needs #t=…&k=…

Drop files to cloak
or browse — up to 500 MB in this preview
Preview: a link opens only on the device that made it
Stored in this browser

A label is yours to choose and stays on this device. It is the one thing here that is not encrypted — write what helps you tell two drops apart, not what the drop contains.

Filenames are inside the encrypted manifest, so this list cannot show them — without the key from the link there is nothing here to read. It can delete a drop, which is what you need when the link is gone.
What it does show — how many drops, how large, when — is on this screen for anyone standing behind you. On a machine you do not control, close this view when you are done.

Stops opening after
Password optional

Without one, the link carries the key: whoever forwards it forwards the files. With one, the link is useless on its own — say the password on the phone, not in the same message. Eight characters is the minimum; three or four words beat eight random characters, and they survive a phone call.

This link will open on this device only. Nothing is uploaded, so whoever you send it to sees an empty page. Carrying a drop to someone else is what the relay will do — it is not built yet.

Cloaking…
Encrypting locally — nothing has left your device
Cloaked.

The key is in this link. Anyone who gets the whole link gets the files — treat it like the files themselves. It stops opening after 24 hours, and after that the app removes the encrypted pieces the next time you open it. The button below does it now, for real.

The key is not in this link. It is wrapped with your password, so the link alone opens nothing. Send the password by another route — on the phone, in person, anywhere but the same message. Nobody can recover it for you, not even us: it was never here. It stops opening after 24 hours.

Still this browser only. Nothing was uploaded, so on another device the link shows nothing yet. Carrying drops between browsers is what the relay will do.

Encrypted here · stored here · relay in the works

Cloaked drop Decrypted locally

# Cloaked files,
for your eyes.

This drop was cloaked in this browser. The key came in with the link — decryption happens right here, with nothing fetched from anywhere.

This page is not running. CloakDrop encrypts inside your browser, so without its script nothing on this page works — no button, no drop, no link. Either scripts are switched off for this site, or your browser blocked ours. Nothing was sent anywhere either way; there is no server that could have received it.
Received files

The key is out of the address bar. It was sitting in your history, and in anything mirroring your screen. It lives only in the link now — reloading this page will not bring it back.

### This drop has a password

The key is not in the link — it is wrapped. Ask whoever sent it for the password; they were told to pass it on separately.

That password does not open this drop.

### This link didn't open

Ciphertext only — nothing was uploaded, nothing is fetched

Encrypt · Chunk · Seal

## Under the cloak

Real AES-256 encryption, no accounts, and links that stop opening when you say.

IN
quarterly-report.pdf PDF · 18.7 MB · readable
AES-256-GCM
OUT gx1`Vq9!kM4…7f2^Zr8?pL6 Sealed · 5 chunks

### Cloaked inside your browser

AES-256-GCM runs in your tab, chunk by chunk. Filenames are encrypted too, inside the manifest — plaintext never leaves this tab.

cloakdrop.com/#t=x4…&k=9fQ…Vw2

### The key rides in the link

It lives after the # — the URL fragment. Browsers never send fragments to servers, proxies, or logs.

PDF
PNG
MP4
ZIP
KEY
CSV

### Every file type welcome

Documents, photos, footage, archives — the cloak doesn't care what's inside. A link stops opening after the time you pick — an hour, a day or a week.

Zero knowledge ciphertext only

### We couldn't look if we wanted to

No accounts, no tracking, no data on our side at all — no file, no filename and no key ever leaves this tab. Wrong key, no files: cryptography keeps the promise, not a privacy policy.

Security, spelled out

## No trust required. Verify it.

Every claim on this page maps to a mechanism you can inspect in your browser's dev tools. Nothing is hidden — except your files.

Cipher

### AES-256-GCM via the WebCrypto API

Hardware-accelerated, authenticated encryption — the same primitive password managers rely on.

Key handling

### Generated locally, never transmitted

The key travels only inside the URL fragment (#…), which browsers keep client-side by specification.

Chunking

### 4 MB chunks, unique IV per chunk

An 8-byte random prefix plus a counter guarantees no IV ever repeats under the same key.

Metadata

### Filenames encrypted inside the manifest

The stored record holds ciphertext, sizes, and a timestamp. Nothing readable — and in this build that record never leaves your browser.

Integrity

### Tampering fails loudly

GCM authentication rejects any modified byte — a wrong key or altered ciphertext yields no output at all.

Limits

## Where the edges are

These are the limits this build runs under. All of them are in the code on this page.

Every drop
Up to 500 MB per drop
Links open for up to 7 days
As many drops as this browser has room for
No accounts, anywhere
Start dropping
The limits in detail

FAQ

## Fair questions

Is the encryption real?
Yes. The key is generated by your browser through `crypto.subtle` and never transmitted. Open your dev tools' network tab while you cloak a drop — you will see no request at all, because this build has no relay to send to. The key exists only in your link's fragment.
Is there a server?
Not in this build. Nothing is uploaded; the encrypted chunks go into this browser's IndexedDB and stay there. The relay being built will hold encrypted blobs, their sizes, and a creation timestamp — no filenames, no content, no key.
What happens if I lose the link?
The files are gone. That is what zero knowledge means here: there is no recovery, because we hold nothing that could recover them. Treat the link like the files themselves.
How long does a link keep opening?
As long as you chose before cloaking — an hour, a day, or seven days. Transfers are handovers, not archives, so there is no option to keep one forever. The age is checked every time a link is opened; in this build that clock runs in your browser, against the drop's creation timestamp. Deleting a drop is separate and immediate: it removes the encrypted pieces, so the link cannot open again at all.
Can I read the code?
All of it, right now — press `Ctrl+U`. The whole client is one unminified file, because a crypto product that says `trust me` instead of `read it yourself` is asking the wrong thing of you. It is not licensed for redistribution, but reading and checking it needs no licence.

## Ready to drop?

Cloak your first file