
sudo apt-get install ccrypt
For Debian, run these commands:
su -
apt-get install ccrypt
To encrypt a file, cd to its folder and run this command:
ccrypt file_name
Replace "file_name" with the name of your file. You will be asked to submit a password two times. The encrypted file will have the .cpt extension.
To decrypt the file, use now this command and provide the password you assigned to it:
ccrypt -d file_name
That's it!