How would I reconstruct a file (assuming I know which file)?

Help
1

Motivation: I would like to use Amazon Drive, but from reading here it appears that there is no Cryptomater Android interface for Amazon drive. There is also AFAIK no Amazon Drive interface for Linux. But, maybe I could use the Amazon web interface and download a file to a directory and then tell Cryptomater to open it.

I’m ignoring the question of “how do I know which file is the one I want” for the moment.

Questions:

  1. Could this approach work?
  2. What minimum amount of information and directory structure would I need to download to make it work (I suppose the meta files, but what about the parent directory structures?)

Thank you,
Mark

2

We provide a utility to analyze and fix vault structures, that is able to decrypt files even if they don’t fit into a valid directory structure.

All you need is the (valid) masterkey.cryptomator and a “fake” vault structure. This could look like this:

foo/
  masterkey.cryptomator
  d/
    AA/ <-- any 2 base32 characters
      BBBBBBBBBBCCCCCCCCCCDDDDDDDDDD/ <-- any 30 base32 characters
        YOURFILE <-- any multiple of 8 base32 characters

Then run java -jar sanitizer-x.y.z.jar decryptVault -vault /path/to/foo -target /path/to/targetfolder.

This tool is intended for data recovery, not for everyday use. So this might be a bit of a hassle if you want to access said file on a regular basis. But I hope this answers your question.

Edit: Note that you’re unable to decrypt the original file name, as it is cryptographically bound to the directory it belongs to. I.e. you are able to recover not more or less then the file contents.