Guys do you know about passward encryption or how I lock a folder which a passward and user name is stolen.

Answer 1

Tip: add a dot(.) in the first character of your file.

file.txt -> .file.txt
Hidden! aww yiss

Access it?
Just go to settings and tick ("Show hidden files")
Hide it?
Just go to settings and tick ("Hide hidden files")

Answer 2

if it is really important to be secure you can get encrypted USB drives like the Ironkey which uses RSA to access and can be remotely wiped if it is stolen