racket encryption video 4/4 --- image encryption
Channel: Danny Heap
Date: 2012-07-19

Video from http://www.cdf.toronto.edu/~heap/racket_lectures.html on how to
scramble each colour band (red, green, blue) in turn of a patient elephant using DrRacket.  Since the scrambling is a permutation, it can be reversed, much to the relief of said elephant.  Quiz at:

www.cdf.toronto.edu/~heap/Racket/encryption.html    See, also
www.cdf.toronto.edu/~heap/racket_lectures.html