Which encryption algorithm cannot be broken mathematically and does not require the use of a computer?

I'm taking a class on how to make a movie, and it offers some apps that would be in the process. the thing is, i don't have any of those ha. if you have any tips on some apps i could use, that would be awesome. i don't have an iphone, so don't suggest any apps like imovie. i know that this is a weird question, but it would be super for me. : )

Create a class named majors that includes an enumeration for the six majors offered by a college as follows: acc, chem, cis, eng, his, phys. display the enumeration values for the user, then prompt the user to enter a major. display the college division in which the major falls. acc and cis are in the business division, chem and phys are in the science division, and eng and his are in the humanities division. save the file as majors.java.

What are the three uses of a screw?