Let's get you secure.
First you will need a Java runtime environment if you do not have one already. Check out https://www.java.com/en/.
For development you will also need a JDK, or Java Development Kit. The most recent JDK can be found here: https://www.oracle.com/java/technologies/javase-jdk15-downloads.html
To run the application you can either look for the .jar file to download and run. This is all you will need to run the application. Direct link is here: https://github.com/atxarib99/CS4389Project/blob/master/Enkryptor.jar
psst! If this gives you issue try running the .jar from the command line with:
java -jar Enkryptor.jar
If that is not available you can build from source. Download this repository from the download button above. You can then open this in an IDE and run Main.java. Your IDE should be able to build this provided that you have a JDK and a JRE.
If you don't want to use an IDE you can build the project using
javac com/Enkryptor/*.java
Then run the program with
java Main.java
Optionally you can also build the binary with
jar cmvf META-INF/MANIFEST.MF Enkryptor.jar com/Enkryptor
And then run the binary with
java -jar Enkryptor.jar