Cryptkeeper removed from Ubuntu 18.04

I had installed Cryptkeeper in Ubuntu 16.04 lts.
I have upgraded Ubuntu 16.04 to 18.04.

After I upgraded to Ubuntu 18.04 , I completely lost my file which were encrypted through Cryptkeeper in Ubuntu 16.04. There are only folders where I kept my files.

Now when I try to install Cryptkeeper in Ubuntu 18.04 through terminal it says

E: Package 'cryptkeeper' has no installation candidate

Does anyone know how to bring back my files without degrading Ubuntu to 16.04 LTS?
Or, does anyone know of another file encryption program, as easy to install and use as Cryptkeeper, that will work reliably on Ubuntu 18.04 ?

You can use GNOME EncFS Manager as an alternative, it lets you import your old encrypted folders.

To install it from PPA , first run

sudo add-apt-repository ppa:gencfsm/ppa
sudo apt-get update

Then install GNOME EncFS Manager by running

sudo apt install gnome-encfs-manager

Statutory warning: EncFS is not a very secure way to encrypt files, you may consider alternative methods.

Cryptkeeper's just a front-end for EncFS, so you could at least install & use EncFS directly in a terminal to read your old encrypted files.

The package is called encfs so install that (you'll have to enable the universe repository if it's not enabled already) and basically just run

encfs ~/encrypted-folder ~/mount-point

Or you could attempt to install the older version of cryptkeeper, by downloading it's .deb file from Ubuntu's packages webpage for xenial here https://packages.ubuntu.com/xenial/cryptkeeper then attempting to install it with

dpkg -i file.deb

But it's not at all guaranteed to work correctly, or at all, or even install.