Experiences in teaching data concealment and data encryption to engineering undergraduates

Students of the undergraduate course Introduction to Informatics get acquainted with the most prevalent methods of data concealment (steganography) and data encryption in history as well as with up to date applications. To teach Cryptography and Steganography is complicated, because you need to plot figures and tables at the blackboard plus calculating the frequency of characters in the text is consuming a lot of work and time. Concealing information within pictures or voices is impossible to show on the blackboard and you can only partially explain how to apply the LSB (least significant bit) technique. Therefore I have devised some applications which are appropriate to show all these algorithms. I wanted to know the usefulness of all the programs I wrote and an excellent opportunity presented itself by the big number of admitted new students. These engineering students attended my lectures held at different dates in two groups. In the first group of lectures I presented and used the programs described above while the lectures for the second group were delivered without these materials. An analysis of the results (Levene test) showed the variance of the two groups different (p<;0,05). In this case the means could be compared with Welch´s t test. This showed a difference between the means (p<;0,05): the mean of the results of students attending the multimedia lectures were better by one mark than the results of the other group where lectures were delivered without multimedia presentations. Calculating the Eta-squared I tried to make percentable the effect of the programs presented based on the result of the papers written and got a surprising 32%. This means a moderately strong correlation existing between the programs and presentations used throughout the lectures of the term and the results of the papers written by the students at the end of term.