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? This unit, developed by computer science non-profit Code.org, tackles these questions. The curriculum is aligned to AP Curriculum Framework standards and the AP CS Principles assessment. Users can navigate through the unit's nine chapters using the circular numbers at the top of the page, or by selecting the links in the blue rectangles on the upper right. These chapters delve into topics such as Simple Encryptions and Public Key Cryptography, each with a Teaching Guide (containing activities ranging from 20-40 minutes long on average), learning Objectives, associated Links, and Support links. Some sections also contain Vocabulary definitions. All lessons and handouts can be downloaded as PDFs via the menu at the top of the site. Also accessible from the Unit 4 landing page are Other Resources related to big data and privacy, such as activity guides, worksheets, and educational videos.