Security
Slate encrypts your notes on your device before they leave it. File and folder names are encrypted along with the notes. The server that passes them between your devices, the relay, never has the key. This page says what that protects, what it does not, and what is still unfinished.
What the relay can see#
The relay stores and forwards encrypted notes. It cannot open them. It does see the traffic around them.
It never sees
- the text of any note
- the name of any file or folder
- any of your keys
It sees
- the email address on your account
- random identifiers for your vaults, pages and devices, never their names
- when each device syncs, and how much it sends
- which devices belong to the same vault, and when a vault was set up again from scratch
- that one device keeps asking about one vault, so its activity can be followed over time
What a hostile relay cannot do#
Suppose someone who wants your notes runs the relay. This is what they can try, and what happens.
Every note is encrypted and carries its own integrity check. If one bit changes, it does not open, and Slate reports an error.
Each encrypted note is bound to its place. Served anywhere else, it does not open.
Your device keeps its own record of what it was given. If the relay tells a different story later, the device stops with an error and accepts nothing.
The record of a page only grows. If the relay drops the end of it, your device sees an old version, never a false one.
That looks like a slow network. Your device shows what it has and catches up when an honest server answers.
Your devices check what they received against each other every time they sync, so a split comes to light; the one thing a relay can still do is keep them apart for ever, which stops both of them and shows up as a device that has gone quiet.
A relay can refuse to pass on the key, and then the new device simply never starts: you see it fail to join, and nothing on the devices you already have is touched.
Where the security review stands#
Slate's encryption has not yet had an external security review. That review becomes a priority as Slate approaches a wider, public release. Until then, a cryptographic design document describes the end-to-end encryption, so that the design can be read and challenged.
Read the cryptographic design document (PDF)
One person builds Slate, with an assistant, and the source is not published. This page says so because a padlock icon would otherwise claim more than is true.
Report a weakness#
If you find a weakness, write to the address below. Say what you did and what you saw. A proof of concept helps. There is no reward programme.
security@slateoutliner.com, also published at /.well-known/security.txt.