I am using Tresorit on Mac OS X and iPhone.

When I am using it there is always applied client-side encryption before posting the file to cloud. The key used for encryption is AES-256 and CFB mode of operation is used.

But I can't figure out how is the key generated and where is stored. Also how is the key transferred or generated on iOS when you would like to access files from two different OSs.

The only information you are providing in registration is your email and password. There is application Tresorit.app on Mac OS X where I tried to find the clien-side encryption key but with no success (there are only certificates of Tresorit and Starcom).

So how this works? Where I can find my AES-256 key?

  • 1
    A lot of information on how their encryption techniques work are detailed in their White Paper tresorit.com/tresoritwhitepaper.pdf
    – ajkblue
    Mar 10, 2015 at 17:36
  • I know about the white paper but there is only general information and nothing in detail, nothing about how is client-side encryption key generated and stored on the client computer and how it is managed across different devices... Mar 10, 2015 at 18:34

1 Answer 1


I know this is a late answer, but might still be interesting for others:

The whole process is very well explained in the link below. When you sign in on a device for the first time it downloads your roaming profile from the Tresorit server. It then decrypts you master key from the profile using your password and the master salt (also in your profile, only part not encrypted).


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