There are more options available that will allow you to do the same. In this guide we will use KeePassX, which is open source and you remain in full control of your keys and files. Make sure you remember to save each time you edit the file, and to remember to create backups of the files. Also, it may be a good idea to test the file on your backup device to make sure it didn't get corrupted.
KeePassX - https://www.keepassx.org/downloads
KeePassX is available for Windows, Mac and Linux. It is a simple and effective tool where you can encrypt private keys and passwords. You are also able to generate secure passwords to use everywhere. The basic usage of KeePassX is very simple, create a file, add a password/private key, save.
Personally I use KeePassX to manage most of my passwords, it is an easy way to use difficult and different passwords at different locations.
Download KeePassX in the link above, follow install instructions and start the software.