This assignment is due right away,
but there is not that much to hand in. However, you need
to follow the submission instructions precisely. That
means creating the file and folder that you submit at the end in
exactly the specified format, with the specified names. I
am not requesting this simply because I am a fussy person (I'm
not, really.) However, in order to make the grading of
assignments as smooth as possible, I want to be able to automate
some of the busywork of downloading, and extracting, and
displaying your work, and this requires a uniform format.
If you already have Python and IDLE installed on your computer,
you do not need to complete step 1. If you have a Mac,
then Python already is installed, and you can use it as is, but
you might find it easier to do an installation that includes the
interactive development environment IDLE, which is what you will
see me demonstrating in class.
We will use Python 2.7 in this course. (The latest version
of Python is Python 3, but Python 2.7 and Python 3 are not
compatible. Python 2.7 is still in very wide use, and will be
around for another four years or so.)
1. Install Python
Install Python 2.7 from the appropriate link on
this page.
The installation is very simple; just click on the link
corresponding to your computer's operating system, and then
follow the instructions. (For Windows and Mac, you have a choice
between a 32-bit version and a 64-bit version. You
probably want to select the 64-bit version, but if any part of
this installation does not work, you can drop back to 32 bits.)
2. Use Python to decode a message, and test your
installation.
Make a folder in which you will store all your work.
Download the file
conversions.py from the
course website and save it to your course folder.
Open the file
conversions.py from the File
menu in IDLE, and select Run Module from the Run menu.
Then at the prompt in the Python Shell window, type
import conversions
conversions.as_to_hex('xyz')
You should see
'78797a'
appear. This is the hexadecimal encoding of the three-byte
representation of the ASCII string 'xyz'. If you followed
the directions and everything went smoothly, you've completed
the installation. There is one more thing to do to
complete the assignment.
3. Decode a base-64 message, and send a hex response.
Here is a personal welcome message from me to you. I've
encoded it in base 64 so you will have to use the conversion
tools to decode it. (You do not have to
understand how
base64 encoding works to do this assignment, but it's
worth knowing about.) And please, just copy and paste this line
of text, don't try to type it all!
V2VsY29tZSB0byBDU0NJMzM4MS4gV3JpdGUgYmFjayB0byBtZS0taW5jbHVkZSB5b3VyIG5hbWUsIHllYXIgaW4gc2Nob29sLCBhbmQgbWFqb3IgaW4geW91ciByZXBseS4=
Type a response to this message, and encode your response as a
sequence of hex digits.
4. Submit your result
Prepare a text file (.txt) containing two lines of text.
The first line will be the ordinary ASCII representation of my
welcome message. The second line will be the sequence of
hex digits encoding your answer. You can use Notepad on
Windows for this, TextPad on a Mac, or Microsoft Word, but make
sure you save your result in plain text format. Your file
should be called
xxxHW0.txt, where
xxx
is your first initial followed by your last
name. For example, if I were a student in the course, I
would call my file
HStraubingHW0.txt.
Place the file in a folder named
xxxHW0 and
compress the folder to produce a
.zip file,
then submit it through Canvas. (What, you might ask, is
the point of even creating a folder, much less compressing it,
when the entire assignment consists of one tiny text file?
This is the way you will hand in all your homework assignments,
so I want you to get used to the process.)