Save docrypt.jar wherever you like (e.g. any drive, flash drive, etc.)
Clicking docrypt.jar installs & runs program.
Make sure Java 8 or better is installed. Open a command prompt and type: java -version
If needed, Oracle (Java's owner) has free java install here
If still not working
Open command prompt in same folder as docrypt.jar and type:
java -jar docrypt.jar