securing a flash drive(pen drive)

Hi,
I use a trekstor flash drive(pen drive). Does anyone know if there is a freeware program that encrytps a flash drive in a way

so that the user needs to put in a password each time they want to access files. It would be great if you could put in the

flash drive and the encryption would start up asking for a password even to allow you to view the files.

I have tried remora usb - this does not stop people looking through files though.

Any suggestions?

Thank you.