Testing if a password for an eCryptfs mount is valid I'm using "eCryptfs" on several directories on my dedicated Debian server. I mount them manually via 

mount -t ecryptfs [dir] [mountpoint]


But after some weeks being mounted it's not easy to remember the exact passwords for each directory. I want to make sure that I got the right passwords before unmounting them or rebooting the server. 

I thought of generating an "eCryptfs" signature and comparing it with the directory's "eCryptfs" signature. Which parameters do I need to know and what is the algorithm for the "eCryptfs" signature? And is this the right way to verify my password?
You can use the ecryptfs-add-passphrase command to add a passphrase to your kernel keyring, which will also print the signatures (hashes) to standard out.

Once you've added a passphrase to the keyring, you might want to clear it, using the keyctl command.

eCryptfs uses a PBKDF2-like, key strengthening algorithm of 65536 rounds of SHA512.

(Disclosure: I am one of the authors and maintainers of eCryptfs.)