Memory sd encryption samsung galaxy s7 edge

A

AC Question

Hi,
For extra security I like to encrypty external memory stick in my samsung galaxy s7 edge. I thought I encrypt my phone by going to settings and then security and click encrypt file and setting a password. (They just asked me once for my password.) In order to test my phone. I connect my phone to another unknown laptop. I was expecting that laptop cannot recognise my file in memery sd card. However, it managed to go through my device without asking for password.
I need to encrypt my memory stick incase if I lost my my mobile one day that nobody can get see my files if they remove my memory stick.
I would be grateful if you could help me.
Regards,
David