For a number of years it has been mandatory for companies according to the AVG to protect personal data, if you do not do this, high fines can even be imposed. Suppose a notebook is stolen or you leave it somewhere in a public space and it contains personal data of customers, then you are dealing with a data breach and fines can follow. To prevent this, you should use encryption to secure this data. No one but the person with the key can access your files.
For iMac this is a standard feature, called FileVault, in Windows Bitlocker is a nice option. GnuPG is the most widely used encryption tool on the Linux platform.
In the IT world, this option is still too often on the to-do list of companies. At the bottom of...