I have previously written about the issue of files being zipped when they make the transiton into Blackboard. I have now become aware of other reason that things may become zipped when they are attached. This comes from the "Behind the Blackboard" knowledge base and I thought it was something that you shoud be aware of. They have also provided some alternative suggestions.
When files uploaded by students are corrupted
Issue
There are instances where Instructors are downloading student assignment submissions which are corrupted. In some instances this corruption has occurred unintentionally through a glitch in the process, however in other instances students have deliberately uploaded corrupted files in order to gain extensions on their submissions.
Symptoms
Problems that the instructor may encounter are:
Downloading a zip file that cannot be opened
Downloading a Word document or PDF submission that is unreadable
SafeAssign cannot process the corrupted document
Cause
The nature of a corrupted file is that it cannot be opened or read by the intended program. Hence there is no straightforward way to determine whether the corruption occurred unintentionally through some glitch in the normal course of business (for example the students computer could have inadvertently corrupted the file while saving, or there may have been internet connection issues when uploading the file) or whether the student has uploaded a file which is deliberately corrupted.
There are companies that are now selling to students pre-corrupted files. One such website that has been brought to our attention is http://www.corrupted-files.com/Home.html . This website offers students corrupted Word, Excel, PowerPoint and other files that they can send to their Instructors in order to buy more time to finish the assignment. By the time that the Instructor has noticed that they cannot open the file, the student can then send "another copy" of the assignment - now completed with the extra time that they have had to complete it.
Analysis
There is no easy way to determine whether a file was deliberately corrupted. A teacher will need to base their decision on the student's own integrity. There are measures that can reduce the chance of innocent users submitting corrupted files and other methods that can help reduce the risk of such cheating. If you have methods that you or your institution employ please feel free to leave a comment below and we will add these to the list.
Workaround
One way to reduce the risk of inadvertent corruption is to have the student submit their assignments in two formats. For example in both Word and as a plain text file or HTML file. Plain text and HTML files are far less likely to be corrupted and can always be opened, even if parts of the file are missing. More importantly, the odds of both files being simultaneously corrupted without the student noticing are very low.
Even a deliberately corrupted file can still be viewed in a hex-editor (such as UltraEdit), and any actual text can be extracted from it with a number of data recovery tools. Therefore it IS typically possible (although very technical and not for the faint of heart) to prove that a given file was NOT actually an attempt at homework X but rather some generic document. Advising students of this early on and threatening them with disciplinary action if they are found cheating are the most successful prevention methods.
Nancy