An Engineering Outlook On Story-telling (Part 3)

Example 3: Story-telling to support learners in memorizing subject matter

The Topic: In Data Structures and Algorithms Course, there’s a subject that covers some elementary content related to ‘encryption’. One of the initial methods of encryption was mono-alphabetic cipher. In a mono-alphabetic cipher, each letter in the primary alphabet is substituted with a new letter from the cipher alphabet. That is, e’ might be substituted with ‘S’, ‘a’ might be substituted with ‘M’, and ‘r’ might be substituted with ‘F’. Therefore, the primary word ‘ear’ is encrypted as ‘SMF’.

We may think that learning basic is kind of boring. Let’s have a look at some historical context cited in the exceptional book - The Code Book, by Simon Singh.

The Story: The past account that is employed to explain the topic is from the 16th century and connects with two cousins, Mary Queen of Scots and Queen Elizabeth, who both desired to be Queen of England. Queen Elizabeth had Mary Queen of Scots incarcerated and was probing some devious way to have Mary slayed so that Elizabeth’s entitlement to the power would be unchallenged.

On the morning of Wednesday, 15 October 1586, Queen Mary arrived at the jam-packed courtroom at Fotheringhay Castle. The long span of detention and initial stages of rheumatism had exposed her strain, yet she stayed gracious, tranquil and unquestionably ceremonial. Abetted by her doctor, she made her way past the juries, bureaucrats, and onlookers, and moved toward the throne that was halfway along the extended, constricted hall. Mary had expected that the throne was a sign of esteem towards her, but she was incorrect.

The seat of command represented Queen Elizabeth, Mary’s nemesis and prosecutor who was preoccupied. Mary was gently guided away from the throne and towards the contrasting side of the room, to the defendant’s seat, a cherry velvet chair.

Mary Queen of Scots was on court-martial for betrayal and subversion. She had been indicted of scheming to murder Queen Elizabeth in order to grab the English crown for herself. Sir Francis Walsingham, Elizabeth’s Chief Administrator, had already detained the other connivers, hauled out declarations of guilt, and executed them. Now he strategized to substantiate that Mary was at the crux of the conspiracy, and was therefore likewise liable and likewise deserves execution.

At this point, we give a dramatic pause with story for the pupils to get hooked. The mentor may explain about mono-alphabetic ciphers - mono-alphabetic ciphers are an encryption plan where letters in primary alphabets are exchanged with letters from a cipher alphabet.

The Teacher may also deliberate on the variance between ciphers and codes. Codes are swaps where words are replaced with symbols that represent the words. So, for example, all manifestations of the word ‘king’ might be switched by the symbol ‘◊’. The Teacher at this point defines that using just ciphers is called enciphering and using just codes is called encoding, but using both is called encryption.

Back to the historical story, Queen Elizabeth was looking for some evidence that Queen Mary was conspiring to have her eliminated. One of Queen Mary’s admirers, Anthony Babington, was sneaking encrypted letters to and from her while she was in penitentiary.

A letter from Babington to Mary comprised the ensuing text that was surreptitiously seized and decrypted by Queen Elizabeth’s principal detective:

Myself with ten gentlemen and a hundred of our followers will undertake the delivery of your royal person from the hands of your enemies…who for the zeal they bear to the Catholic cause and your Majesty’s service will undertake this tragic execution.

This indicated that Mary’s supporters were certainly scheming to kill Queen Elizabeth. But, Queen Mary had to give her nod to the scheme to be part and lead in the offense. Eventually, Mary sent the following encrypted response:

I will be glad … to give you some further advice necessary to be followed therein, as also from time to time particularly how to proceed.

This, without any ray of doubt, was Mary approving the murder of her cousin Elizabeth.

At this point, the mentor may explain frequency analysis which is a technique employed to decide the regularity of letters arising in the encrypted message. The regularity of letters in the encrypted message is compared with the frequency of letters in a typical un-encrypted page of text.

For example, in a page of any given novel, the letter ‘c’ will occur approximately 8.1% of the time. Therefore, any letter occurring in the encrypted message approximately 8% of the time has some likelihood of being the letter ‘c’.

The scholars work on some simple example of decryption (perhaps the above letters to and from Queen Mary). Finally, we read the sad and horrible finish to the extraordinary tale: This narration is written by Richard Wingfield, who presumably, was present at the execution on

February 8, 1587.

“Then she laide herself upon the blocke most quietlie, & stretching out her armes and legges cryed out … & at the laste while one of the executioners held her slightlie with one of his handes, the other gave two strokes with an axe before he cutt off her head …”

(Note the frequency of ‘e’ ‘t’ and ‘g’in the text)

The Lesson: The story is about encryption. The study topic could be explained with or without the historic perspective, but the history certainly enhances influence. By the end of the lesson, the students would have learned about enciphering, encoding, encryption, mono-alphabetic ciphers, frequency analysis, and a small piece of English history.

P.S. Using historical stories in teaching the technical lessons contributes greatly to its perspective and profundity, and makes students plot points to memorize the elements of the topic of study.

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