File Security

Fall 2004

As discussed in class, it is the responsibility of each student to prevent other students from obtaining any progamming files. Should any instances of cheating be discovered, both students will (at least) receive a grade of 0 on the programming assignment, and lose one letter grade on their final grades for the course. So, please take all necessary steps to ensure that no one can access your programming files. This page will show you how to change the file permissions using the web site, so that only you can access your files through a computer.

Getting Started

On the website, click on the link for FTP. On this page, login using your ecelrc password (just as you would to use one of the computers in the lab). After logging in, the page will show the files in your home directory. The directories within your home directory will be listed on the upper half of your screen, with the files on the lower half. If the file whose permissions you wish to change are not in your home directory, simply click on the name of the directory which contains the file and that directory will open.

File Permissions

The permissions for a file detail who can access a file and how they are permitted to interact with the file. There are three permission classifications: owner, group, and world. For your program files, you are the owner, the group corresponds to all students, and the world is anyone who chooses to try and view your files. Each group has three settings: read, write, and execute. Read access allows the person trying to access the file to view it. Write access gives that person the ability to change the file. Finally, execute access allows the person to run the file.

Changing File Permissions

In the case of your programs, it is important that you (the owner) alone have permission to read, write, and execute the file. To change your file permissions after you have logged in, find the file whose permissions you would like to edit and check the box next to that file. Now, click the Permissions on the left side of the page. This will bring up a page which shows the current permissions. To set the permissions so that only you have access to the file, check the Read, Write and Execute boxes under the owner group, and clear any checks in boxes under other groups. Alternatively, you could enter the octal representation 700 in the box. This will ensure that only you have access to that file.