Crypstie

A pastebin alternative with the highest security level


The Crypstie, very much like other services like pastebin, allow you to “paste” any data and turn it into a URI link, that can easily be passed to others using messengers, SMS and so on. Very good for long texts. Also, it applies syntax colouring for better readability.

But the strongest point of the Crypstie is the highest security level.

What means highest security level?

It means that whatever data you paste as crypstie, only those in posession of the full URI link will be able to get access to it. Even the service itself won’t be able to decrypt it, as the encryption key is never sent to the service. All cryptography is performed in the browser locally, without transmitting the key to the service. It is the Universa way.

And this is not just a promise to not to. By design, the whole URI is needed to decrypt data stored on our servers. And we do not have the dull URI - only part of it which the browser passes to the HTTP server, e.g. all but the hash (or fragment) which is needed to decrypt it.

How is it done?

Very simple. We take advantage of the hash part (aka fragment) of the URI. The hash part is something that goes after # sign in the URI, for example:

Hash part is never sent to the server! When the browser opens a page, it extracts the fragment from the link, and send the rest to the service to obtain the page, without the fragment. Crypstie stores the encrypted data on the service, and put the key to the hash, so the browser can decrypt it, but the service can’t. Let’s see it on the diagram:

As we can see, the protected text is encrypted and decrypted only on the browser page. The key is never transferred to the service, so the service could not decrypt the information under any circumstances. So, only those who receive the whole crypstie URL (including hash), will be able to access it. Maximum confidentiality, the Universa way.

How does it work?

  1. Create new crypstie by pasting any the text to the big window.
  2. Select expiration time from dropdown list.
  3. Add the optional name, if needed. It will be encrypted too and won’t be visible to the service.
  4. Push “create” button. The browser will generate cryptographically strong random key, encrypt the text and the name and send it to the service.
  5. The service will store encrypted data and return non-hash part of the URI to open it.
  6. Browser will add key to the hash part and open the resulting secure URI, so you immediately see the result. The syntax colouring is applied automatically based on the content.
  7. Copy the secret link from the field below (click it three times to select the whole), and paste it to some messenger, SMS, docs page, whatever.

Have a nice time with crypsties!