During installation, many Linux distros like Ubuntu and Elementary OS etc asks you to encrypt your hard drive using LVM encryption. This simply makes all you data encrypted and one with its password can only open you laptop to use operating system or access your data files.
Even if your hard drive is connected via USB or something to another operating system , the encryption asks the user to enter the passphrase in order to access files and other data.
In this lesson you will learn about changing the passphrase i.e. password of an encrypted LVM system.
Start by opening terminal of your Linux distro and then run the following command. As soon you paste this command and press ENTER, it asks you to enter your admin password.
sudo cryptsetup luksChangeKey /dev/sda5
Then, another ENTER asks you to enter your old passphrase and then it allows you to change your passphrase simply by typing a new one.
Removing old passphrase: If you don’t want encryption any more on your hard disk then you can easily remove it with this command:
sudo cryptsetup luksRemoveKey /dev/sda5
Alternatively you may download “Disks” from your Linux Software Manager. Run it to select your encrypted device partition and then click gear icon followed by “Change passphrase” option.