The private line, explained.
ClearSky™ is the end-to-end encrypted transfer technology inside OneSpace. Files are encrypted on your device, and only your recipient’s device can open them. Our servers only route them in encrypted form. This page walks through exactly what happens when you press send, and why we couldn’t read your files if we wanted to.
What we never see.
Most services ask you to trust their policy. ClearSky is built so you don’t have to trust anyone, including us.
Not your files
No readable file on our servers. Ever. Files only pass through them in encrypted form, so there’s no readable copy sitting anywhere to breach, subpoena, or leak.
Not your keys
Encryption keys are created on your devices, and our servers only ever hold them sealed. We couldn’t read your files if we wanted to. We built it that way on purpose.
Nothing to hand over
No readable files and no usable keys on our side means nobody can take your files from us in readable form, and we have none to hand over. Not a policy promise. A mathematical one.
Five steps. Two devices. Nobody in between can read it.
You add each other
You and your recipient add one another as contacts, by username. Being each other’s contact creates a private connection between your devices, and your devices exchange public keys. Strangers can’t send you anything.
A fresh key for every file
For every file, your device makes a new random key and seals it with your recipient’s public key, so only their device can open it. Our servers hold nothing but that sealed key.
Sealed on your device
Before a file goes anywhere, ClearSky encrypts it with XSalsa20-Poly1305 (256-bit keys), on the device itself. Nothing readable ever leaves your device.
Routed in encrypted form
Our servers route the file to their device in encrypted pieces and never see a readable byte. A Live Transfer is cleared the moment it finishes, and other transfers are deleted after delivery.
Opened on theirs. Only theirs.
The receiving device decrypts the file on arrival. Your readable file now exists in exactly two places: your device and theirs. That’s the whole trip.
Nobody in between can read it. Not even us.
This is what a live transfer looks like.
A real transfer running in the app, shown on the map. What you see here is step 04 happening: the file is already encrypted, and our servers hold at most a few encrypted pieces at a time, never the whole file.
Encryption, specifically.
Every transfer is protected end to end with XSalsa20-Poly1305 (256-bit keys). The file is encrypted on your device before it moves, stays encrypted the whole way while our servers route it to your recipient, and is decrypted only on the receiving device. XSalsa20 is a modern alternative to AES. Its close relative ChaCha20 is one of the standard ciphers in TLS 1.3, the protocol behind HTTPS.
Keys are generated on your devices. When you pair with a contact, your devices exchange public keys. Each file gets its own random key, sealed to your recipient’s public key, and your account password is protected with Argon2id. Our servers store only sealed keys they can’t open.
And there’s nothing for you to configure: no hassle with PGP keys or your own key infrastructure. OneSpace is ready to use straight out of the box, on Windows, macOS, iOS and Android.
ClearSky™ at a glance
- Encryption
- XSalsa20-Poly1305 (256-bit keys), end to end
- Route
- Your device to theirs, routed by our servers in encrypted form
- Keys
- Generated on your devices; our servers hold only sealed copies
- Key exchange
- Public keys at pairing · a random key per file, sealed to the recipient
- On our servers
- Encrypted only, deleted after delivery
- Cloud storage
- No readable files, ever
- Transfer limits
- Free: 2 sends a month up to 1 GB. Premium: no monthly limit, no file-size limit
- Platforms
- Windows · macOS · iOS · Android
The honest part.
A private line has properties a cloud locker doesn’t. We’d rather you know them before you buy.
Live Transfer needs both devices online
A Live Transfer streams while you’re both online. If your recipient isn’t on yet, they get a notification, and an ordinary transfer waits for them, encrypted.
Your file waits, encrypted
Every transfer passes through our servers in encrypted form. A Live Transfer is cleared the moment it finishes. Other transfers are deleted after delivery, or expire if nobody collects them. We couldn’t read it in between.
The web demo works differently
The free web demo encrypts in your browser and hands the file over through our broker, and the link expires after 24 hours. It’s a taste of OneSpace. The full product adds contacts, groups and sync, with the same end-to-end encryption.
Not our first encryption product.
ClearSky™ comes from the team that built the encryption software shipped with storage products from the world’s leading brands, protecting files at retail scale, long before OneSpace.
That work reached over 150,000 customers and protected hundreds of millions of secure deliveries. Quietly, reliably, for more than a decade.
OneSpace, powered by ClearSky, is what we built next. ClearSky launched in the United States in 2024.
With OneSpace, nobody in between can read your files. Not even us. That gives people peace of mind: their files stay private and under their own control.
Our security software shipped with products from
Straight answers.
How is this different from cloud services that offer end-to-end encryption?
Encryption is only half the story. The other half is where your file lives. A cloud service, encrypted or not, still holds a copy of your file on its servers. With ClearSky, our servers only route your file in encrypted form and delete it after delivery, so there is no readable copy anywhere to breach, subpoena, or leak.
What can OneSpace see when I send a file?
Not the file. It’s encrypted on your device with a key only your recipient can open, and our servers only route it in encrypted form. We can see that a transfer happened (who, when, how big), never what’s in it.
Do both devices need to be online at the same time?
Only for Live Transfer. Ordinary transfers wait for your recipient, encrypted, and they get a notification. If you just need to hand someone a file from a browser, the free web demo covers that.
What if my recipient is offline?
Your file waits on our servers, encrypted, and they get a notification. It’s deleted after they download it, or expires if they never do. We can’t read it while it waits.
Do I need to set up PGP keys or certificates?
No. When you add a contact, your devices exchange public keys automatically, and every file gets its own key, sealed to your recipient. There’s no PGP hassle and no key infrastructure of your own to run. OneSpace is ready to use straight out of the box.
Is the free web demo the same as ClearSky?
No, and we’re upfront about that. The web demo encrypts a file in your browser and hands it over through our broker, and the link expires after 24 hours. It’s a taste of OneSpace. The full product goes further: contacts, groups and sync, with the same end-to-end encryption.
Put ClearSky™ between your devices.
One license covers Windows, macOS, iOS and Android. Monthly, yearly or forever.
Lifetime license €179.99 · one payment · 14-day money-back
Found a security issue? [email protected]