Cryptology and Cybersecurity for Young Scholars ~ Part Two: Crack the Code!

This is the second in a series of posts related to the study of CRYPTOLOGY for advanced students in grades 3-5. See also: Part One: The History of Codes and Ciphers ~ FIND A VIRTUAL SLIDE SHOW READY-TO-SHARE WITH STUDENTS HERE!

In Part One, students were introduced to CRYPTOLOGY as the study of the history of codes and ciphers and the science of making and breaking them. Several introductory activities exposed students to the uses of codes and ciphers over time as well as some of the language of the discipline.

Part Two of this unit is about CODES ~ what they are, their purposes, and a few ways codes have been used in cryptology. Students will also learn how codes differ from ciphers (see Part Three: Decipher This! – coming soon).

WHAT IS A CODE?- In the brainstorming session in Part One, students shared everything they associate with the word “code,” and many “codes” on the list probably had little to do with cryptology. Return to the list students came up with and add to it by asking students to consider multiple perspectives:

What does the word “code” mean to a lawyer? a computer programmer? a school principal? a builder? a scientist? a police officer? a medical doctor? a pilot?

Depending on students’ prior knowledge, additional words elicited might include: codes of law, HTML codes, building codes, genetic codes, radio codes, hospital codes such as “Code Blue,” etc. Ask students to mentally categorize them in ways that make sense to them (patterns, rules). There are no right or wrong ways to do the grouping. Discuss students’ ideas.

Possible categories might include system codes (codes that perform a practical function, such as zip codes, and barcodes), rapid communication codes (codes for emergencies, computer codes, QR codes, the Morse code), and secret communication codes (codes used to send information with the intention of keeping it secure or secret).

ASK: If you had to use ONE WORD to signify the essence of all CODES, what would it be? Students may say “information,” “rules,” “communication,” “systems,” “messages,” and all could be justified as the commonality among codes. A code is often defined as a set of rules or a system of communication. Symbols, abbreviations, and signals could even be considered codes.

Ask students which codes in the brainstormed list are SECRET, and which ones are NOT SECRET. This may result in a conversation about semantics. How is “secret” defined? For example, the radio codes used by police officers and dispatchers are not really secret but they are specific to those occupations and may be unknown by those who don’t work in law enforcement. What about the codes used for special drills in schools? Are they secret? For example, in our school, we used to use obfuscated* messages for drills, such as ‘Mr. Locker, please report to the office’ to alert teachers of a lockdown drill. NOTE: In addition to introducing the word obfuscation, you may want to discuss other words related to secure communications: confidential, classified, sensitive, etc.

CRYPTONYMS

Display the picture below and ask students what they think it might mean or what they can determine from the wording of the coded message. Ask them how this coded message is different from the one deciphered in Part One (LCNEN 51784LWPHE 51962AOLDS). Elicit the idea that in the message below, code words are replacing regular names of things. Explain that, in cryptology, this is how codes are different from ciphers. In a CODE, a symbol, signal, or cryptonym is used to represent an entire word or phrase. However, in CIPHERS, individual letters are replaced and/or rearranged to encrypt a message.

The cryptonyms, or code names, in the message above have been used by the Secret Service. “Kittyhawk” was a code name for Queen Elizabeth II, and “babysitters” were bodyguards. Introduce the word cryptonym and tie it to other words ending in “nym” such as homonym, antonym, synonym, and pseudonym.

Cryptonyms can be combined with other methods in order to secure a private communication. Ask students if they recall how the Navajo code talkers used cryptonyms (e.g. “turtle” for “tank”) and note that these code words added an additional layer of security to messages sent by radio, even though few people could translate the Navajo language.

Ask students if the video excerpts (from Part One) brought to light any other CODES. They may mention the flag signals used during the Civil War and Morse Code, both of which could be used to send entire words, but were mostly used to spell out individual letters. Most of the secret encryptions we call “codes” are actually ciphers.

There are many lessons you can incorporate into the topic of codes, even though many do not relate to cryptology. Here are some links to several lessons I can recommend:

MORSE CODE – (5-10 min.) Morse Code has an interesting history and an advantage in that it can be transmitted in many ways. Students often want to use the dots and dashes to write out coded messages, so use these slides to explain that it’s more about learning to interpret the rhythm or hear the code. You might also like to incorporate this STEM activity in which students build a telegraph “machine.”

CRACKING THE (BAR) CODE: (45 – 90 min.) My students always enjoyed learning a little more about UPC codes and this lesson is well organized with free resources you can use.

BINARY CODE: It’s truly amazing that all information sent electronically today, including photographs and videos, is transmitted using just two digits: one and zero! I always introduce lessons in binary code by expressing my awe over that fact! Before sharing any further information, I would ask students what they know about bits, bytes, megabytes, and gigabytes and then explain a little about binary code, including a little about pixels.

I’ve used the first lesson in this set with grades 4-8, and have found the hands-on activity with the sets of cards to be the perfect introduction to binary numbers. A similar activity is being demonstrated in the video below. All of these resources can be found HERE.

Once your students have a basic understanding of the binary system, you might want to also share this TedED video. I love the first statement on this video; make sure you return to it and wait for your students to “get it!” You can find the entire TedED lesson here. You can find many other activities for teaching and reinforcing binary code, including making binary bracelets.

An obvious extension of these activities would be to have kids combine cryptonyms, symbols, signals, etc. or come up with some kind of new CODE with a specific purpose. Let us know if you try any of these activities with your students or if you anything to add by leaving a comment below. Next in this series: Part 3: Decipher This!