I forgot the password of a EncFS folder (created, went to vacation, forgot). But I remember how the password was created (e.g. was a sequence of 4 dictionary words). So I decided to try to find the password - even if I'm absolutely not expert in system security.
The only way I know to break a password is with brute force attacks.
Given an EncFS folder including the
.encfs6.xml file, it is possible to test if a password is correct or not by just mounting the folder and providing the password, like has been done here.
But I noticed that this kind of attack is very slow. I would like to try a parallel attack and use a GPU to test the passwords.
I know that to perform "quickly" an attack over the password, is better to get "something" for example the hash of the password, and just compute the hash over the putative passwords until a matching one is found.
But I don't know how EncFS works: I know that
.encfs6.xml is fundamental to decrypt the data, but I don't know what data it contains and how to use it to parallelize my attack.
How does EncFS encrypt the data and how can I use the content of
.encfs6.xml to test if a password is valid, without having to run the encfs utility? (Or, where in the EncFS code I can find the relevant information to answer this question?)
I am also considering to use
openssl for the attack, but I still have to figure out how to use
.encf6.xml information in the command line openssl tool. Not even sure about which algorithm to use: aes-256-what??