Unit 4 - Big Data and Privacy (Last update: October 2016)

The data rich world we live in also introduces many complex questions related to public policy, law, ethics and societal impact. In many ways this unit acts as a unit on current events. It is highly likely that there will be something related to big data, privacy and security going on in the news at any point in time. The major goals of the unit are 1) for students to develop a well-rounded and balanced view about data in the world around them and both the positive and negative effects of it and 2) to understand the basics of how and why modern encryption works.

Many of the lessons that follow have worksheets and student guides associated with activities. Those worksheets are listed in the relevant lesson plan, or you can check out all unit 1 student-facing activity guides here. You can access a flat pdf of all the lessons in unit 4 here.

Chapter 1: The World of Big Data and Encryption

Big Questions

  • What opportunities do large data sets provide for solving problems and creating knowledge?
  • How is cybersecurity impacting the ever-increasing number of Internet users?
  • How does cryptography work?

Enduring Understandings

  • 3.2 Computing facilitates exploration and the discovery of connections in information.
  • 3.3 There are trade offs when representing information as digital data.
  • 4.2 Algorithms can solve many but not all computational problems.
  • 6.3 Cybersecurity is an important concern for the Internet and the systems built on it.
  • 7.1 Computing enhances communication, interaction, and cognition.
  • 7.3 Computing has a global affect -- both beneficial and harmful -- on people and society.
  • 7.4 Computing innovations influence and are influenced by the economic, social, and cultural contexts in which they are designed and used.

Week 1

Lesson 1: What is Big Data?

In this lesson, students are introduced to the concept of “big data,” where it comes from, what makes it “big,” and how people use big data to solve problems. Students are asked to consider how much of their lives are “datafied” or could be, and the teacher will show the projected growth of data in the world. Students will then investigate a big data tool in pairs to evaluate the tool for its usefulness and investigate the source of the data used to make the tool. A key take-away from the lesson is that different considerations need to be made when trying to look at, use, or analyze tools that use big data. The world of big data is big, and we’ve only begun to figure out how to solve problems with it.

Teacher Links: Video | Student Links: |

Lesson 2: Rapid Research - Data Innovations

In this lesson students will conduct a small amount of research to explore a computing innovation that leverages the use of data. Students will research a topic of personal interest and respond to questions about about how that innovation produces, uses, or consumes data. The lesson is intended to give students practice with doing research of this nature and provides a small amount of scaffolding to help students figure out what to look for.

Teacher Links: Student Links: Video | Video | Video | | |

Lesson 3: Identifying People With Data

Students begin this lesson by investigating some of the world’s biggest data breaches to get a sense for how frequently data breaches happen within companies and organizations, and what kinds of data and information is lost or given up. Afterwards, students will use the Data Privacy Lab tool to investigate just how easily they could be uniquely identified with a few seemingly innocuous pieces of information. At the conclusion of the lesson, students will research themselves online to determine just how much someone could learn about them by conducting the same searches and “connecting the dots.”

Teacher Links: Student Links: Web Site | Web Site | |

Week 2

Lesson 4: The Cost of Free

This lesson focuses on the economic and consumer concerns around apps and websites that collect and track data about you in exchange for providing you a service free of cost. Often the quality of the service itself is dependent on having access to data about many people and their behavior. The main take-away of the lesson is that students should be more informed consumers of the technology around them. They should be able to explain some of the tradeoffs between maintaining personal privacy and using innovative software free of cost.

Teacher Links: Student Links: Video | External Article | Article | |

Lesson 5: Simple Encryption

In this lesson, students are introduced to the need for encryption and simple techniques for breaking (or cracking) secret messages. Students try their own hand at cracking a message encoded with the classic Caesar cipher and also a Random Substitution Cipher. Students should become well-acquainted with idea that in an age of powerful computational tools, techniques of encryption will need to be more sophisticated. The most important aspect of this lesson is to understand how and why encryption plays a role in all of our lives every day on the Internet, and that making good encryption is not trivial. Students will get their feet wet with understanding the considerations that must go into making strong encryption in the face of powerful computational tools that can be used to crack it. The need for secrecy when sending bits over the Internet is important for anyone using the Internet.

Student Links: Widget | Widget |

Week 3

Lesson 6: Encryption with Keys and Passwords

In this lesson, students learn about the relationship between cryptographic keys and passwords. Students explore the Vigenère cipher with a widget to examine how a cryptographic “key” can be used to encrypt and decrypt a message. Then, students use a tool that shows them about how long it would take to crack a given password using a standard desktop computer. Students experiment with what makes a good password and answer questions about the “human components” of cybersecurity.

Teacher Links: Answer Key | Answer Key Student Links: Worksheet | Widget | Worksheet | Code Studio Page | Video | Resource |

Optional Lesson: Hard Problems - Traveling Salesperson Problem


In this lesson, students examine a classic problem in computer science, the Traveling Salesperson Problem (TSP). Students solve small instances of the problem, try to formulate algorithms to solve it, and discuss why these algorithms take a long time for computers (and humans) to compute. Students see how the TSP grows in size much faster than the problem of adding characters to a password. Even though we use encryption to motivate a desire to learn about computationally hard problems, they are valuable to know about, in and of themselves. This lesson covers some territory about how we reason formally and mathematically about algorithms and figuring out how “hard” something is for a computer to do.

Teacher Links: Student Links: Worksheet

Optional Lesson: One-way Functions - The WiFi Hotspot Problem


In this lesson, students continue their exploration of computationally hard problems as they investigate a one-way function, a problem which is easy to construct in such a way that you know the solution, but it is computationally hard to solve. Students will begin the lesson by trying to solve the “Wireless Hotspot Problem” (also know as the vertex cover or dominating sets problem) to experience first-hand the challenge of solving it. They will then be instructed on how easy it is to create such a problem and will practice doing so themselves. In the Wrap-up, students are introduced to the concept of a one-way function and consider why such problems might be useful tools when constructing methods of encryption. If it’s easy to create a problem that is hard for a computer (or human!) to solve, then perhaps it is possible to make truly secure encryptions.

Teacher Links: Answer Key | Answer Key | Student Links: Worksheet | Worksheet

Lesson 7: Public Key Cryptography

This is a big multi-part lesson that introduces the concept of public key cryptography which is an answer to the crucial question: How can two people send encrypted messages back and forth over insecure channels (the Internet) without meeting ahead of time to agree on a secret key? In a nutshell, there are two main principles we want students to understand:

Teacher Links: Answer Key | Teacher Guide | Teacher Guide | Teacher Demonstration Guide Student Links: Activity Guide | Activity Guide | Code Studio | Video | Handout | Resource

Lesson 8: Rapid Research - Cybercrime


In this brief lesson students learn about various types of cyber attacks and cyber crimes and do a small amount of research to learn more about one. The lesson should cap off learning about encryption by taking a moment to look at the kinds of attacks and threats encryption (among other things) is intended to thwart. The lesson is intended to be a transition as well, to kick off a Practice Peformance Task that begins in the next lesson about Big Data and Security more generally.

Teacher Links: Answer Key Student Links: Video Worksheet | Web Resource | Video | Activity Guide

Week 4

Lesson 9: Practice PT - Big Data and Cybersecurity Dilemmas

To conclude their study of big data and cryptography, students will complete a small research project related to a dilemma presented by Big Data or Cybersecurity, in the form of a Practice Performance Task. Students will pick one of two issues to research more deeply - either an issue related to big data, or one related to cybersecurity. Students will need to identify appropriate online resources to learn about the functionality, context, and impact of the technological innovation that gave rise to the dilemma they are investigating. After completing their research, students will present their findings both in a written summary and with an audio / visual artifact they found online. The written components students must complete are similar to those students will see in the AP Performance Tasks.

Student Links: Practice PT |

Chapter Commentary

Content and Teaching Strategies

In many ways this unit acts like a current events unit since it is highly likely that there will be something related to big data, privacy and security going on in the news at any point in time. The major goals of the unit are 1) for students to develop a well-rounded and balanced view about data in the world around them and both the positive and negative effects of it and 2) to understand the basics of how and why modern encryption works.

Most of the activities in these first two weeks call for students doing research online, using some online tools to investigate issues, as well as discussing and writing about the issues. The first week could be loosely titled “Big Data is Great!” - in which students investigate how data is being used in a field or area of personal interest. The second week could be loosely titled “Big Data is Scary” - in which students see how much data about people (including them) is collected by companies, governments and other organizations, and that we often give this data away freely in exchange for a free service.

The activities in the third week around data encryption should look and feel similar to lessons from Units 1 and 2. The general pattern is to introduce a concept through an unplugged activity or thinking prompt, and then “plug it in” by using a widget to explore the concept further. The purpose of the widgets is to allow students time to play with some of the ideas - often mathematical in nature - to get sense for how they work. In particular students should come away with a high level understanding of how asymmetric encryption works and why it makes certain things possible (sending encrypted data without a shared key) and certain things basically impossible (cracking a key).

Why do it this way? • The Role of the Teacher

Many of the lessons in this unit are designed as practice for elements of the Explore Performance Task. In particular lesson 2 “Rapid Research” is good practice for the kind of relatively quick research and writing students will have to do for the Explore PT. The goal is for students to become facile with looking up sources, reading/skimming articles for their main points, and being able to explain both sides of an argument or dilemma related to big data, security and privacy.

During this unit the teacher should remind students about the Explore PT and its various elements - and keep the focus on the PT throughout the unit since really that’s the ultimate goal. Since many of the areas of investigation are open to student choice, the teacher can help by making sure students are making appropriate choices, helping them get “unstuck”, and pushing them to think more deeply and more specifically about the kinds of things they are interested in. In particular you can always ask, how does this use data to do something innovative? Rather than trying to explain a very broad topic, find a small corner of it that you can explain and demonstrate the innovation involved.