The Proof.

Imagine a thief breaks into a bank and gets your deposit box open. Inside, instead of your things, there's a solid block of steel. That's what our servers hold.

When you type your 12 words, you aren't logging into a website. There is no account to log into. You're unlocking something with a key only you have — we never saw it, and we never stored a copy. Without that key, everything we hold is ciphertext.

And because there are no accounts, there are no folders with your name on them either. Your scrambled notes sit in the same shared storage as everyone else's, and nothing in that storage says which pieces belong to whom. So even a thief who took everything would get a pile of locked boxes and no way to tell whose is whose — let alone how to open one.

Most apps turn your password into a key instantly. That speed helps the thief too — a fast computer can try billions of passwords a second. So we did the opposite of fast.

We run your words through Argon2id, which is deliberately slow and deliberate about one thing in particular: memory. Before it will produce your key, it has to hold 64 MB of memory for a few passes. That's not a speed bump — it's a wall. To guess a million passwords at once, a thief doesn't just need a faster chip; they need a million times 64 MB of memory, all at the same time, for every single guess. Nobody has that, and nobody can buy it.

That little pause you feel when you unlock your vault? That's this wall being built, in front of you, every time. The delay you notice is the same cost a thief would have to pay — per guess.

Your vault is locked by twelve words. They're picked at random from a list of 2,048, which sounds small and isn't: twelve picks give you around 340 undecillion possible combinations. That's a 39-digit number — so big that it's more than the number of stars in the entire universe.

Now picture a computer that could try a trillion of those combinations every single second. No such machine exists — that's already far faster than anything ever built. Even at that impossible speed, trying every combination would take about 10 billion billion years. The universe has only been around for 14 billion. You'd need a billion universes, run one after another, to finish one person's words.

Could a quantum computer cheat that? No. The best known quantum shortcut is Grover's algorithm, and all it does is halve the work — like turning a 39-digit lock into a 20-digit one. Still impossible — and you cannot dodge it with a bigger or faster machine, either. The wall here is time, not cleverness: the space is simply too large to walk across.

That is the real guarantee. Not a promise from us — a limit set by the laws of physics, which apply to everyone equally.

Most apps treat “change your password” as a coat of paint. The old locked files are still sitting there, locked with the old key — so anyone who already copied them keeps a working copy.

Changing your words in Prevon actually re-locks everything. Rotating means every stored piece is unlocked with the old words and re-locked with the new ones, and the vault itself is re-keyed at the storage layer. It happens as one single operation: if any part fails, the whole thing doesn't happen, and your old words still work.

And once it succeeds, the old words are dead. They don't unlock your notes — or any copy someone stole before you changed them.

Most cloud sync services keep your files in a folder tied to your account — which means a breach, a subpoena, or a rogue employee only needs to find your folder, not break your encryption. Ghost Sync is designed so there is no folder to find: every user's encrypted notes sit in one shared, undivided pool with nothing that marks which pieces belong to whom. Finding your own data again is a calculation your device performs from your Recovery Seed, not a lookup against an account record we hold. We also pad every encrypted note to a standard size, so a short note and a long one look the same from outside — see padding for the exact buckets. And because there's no account record to check for inactivity, storage that's gone unpaid and unrenewed simply expires on its own — nobody has to go looking for whose data to remove, because nothing points back to a “who” in the first place.

When you throw something away in real life, it's gone. On a phone, it isn't. Deleting a file usually just removes the name, and phone storage quietly moves “deleted” data somewhere else to save wear on the chip — so the old copy can sit there, perfectly readable, for weeks. That's true for SSDs, and it's why “erase” buttons often don't mean what they say.

So we don't chase the data down. We destroy the one thing that could ever make sense of it: the key. The moment you wipe your vault, the key is gone from your device, and every copy of your notes — the one you can see and the hidden ones you can't — turns into static at the same instant. There's nothing left to erase, because nothing left can be read.

We could build a web version. It would be cheaper and easier. It would also quietly undo everything on this page.

A website is not one thing you install — it's code that gets re-sent to you every time you open it. So if anything between you and that server is tampered with, even for five minutes, the code running on your screen can change and you would never see it. A real app is different: it's a signed package that sits on your device, and updates arrive the same signed way. You can check it. You can't do that with a page that rebuilds itself on every refresh.

There's a second reason. A browser tab shares its world with every other tab, extension, and script you have open — and browsers treat data stored by a website as disposable, something to clear when space is tight. Your notes should not be disposable. Prevon runs in an OS-level sandbox that nothing else on your device can look into, and it writes your files exactly once, where they stay until you decide otherwise.

Convenience and control aren't always the same thing. We picked control.