Cryptography in Grade 10: Core Ideas with Snap! and Unplugged

International audienceWe report our experience of an extracurricular online intervention on cryptography in Grade 10. Our first goal is to describe how we taught some fundamental cryptography ideas by making students encounter a progression of representative cryptosystems, from classical to modern, and discover their characteristics and limitations. We used Snap! (a visual programming language) to realize hands-on activities: block-programming playgrounds (a form of task-specific programming languages) to experiment with cryptosystems, and an interactive app to support an unplugged (albeit remote) Diffie-Hellman key agreement. After experimenting with each system, the students were involved in a Socratic discussion on how to overcome the discovered limitations, motivating the introduction of the following system in our path. Our second goal is to evaluate the students' perceptions and learning of cryptography core ideas. They appreciated the course and felt that, despite being remote, it was fun and engaging. According to the students, the course helped them understand the role of cryptography, CS, and Math in society and sparked their interest in cryptography and CS. The final assessment showed that the students well understood the cryptography ideas addressed. Our third goal is to discuss what worked and areas of improvement. The "remote-unplugged" Diffie-Hellman, where the meeting chat was a metaphor for the public channel, engaged the students in understanding this groundbreaking protocol. Overall, they praised the activities as engaging, even when challenging. However, a strong "instructor blindness" induced by remote teaching often prevented us from giving the students the right amount of guidance during the exploration activities

Programmare per imparare la crittografia al Liceo Matematico

Descriviamo un corso di introduzione alle “grandi idee” della crittografia, pensato per il secondo anno del Liceo Matematico. Sua caratteristica fondamentale è l’approccio “per scoperta”: viene proposta una successione di crittosistemi (dai classici ai più moderni), di ciascuno dei quali lo studente puó sperimentare caratteristiche, possibili attacchi e limi- ti, sentendo la necessità di scoprire il successivo. Abbiamo usato Snap! (un linguaggio di programmazione visuale a blocchi) sia per costruire dei playground (linguaggi di pro- grammazione task-specific, con una ridottissima selezione mirata di istruzioni) con cui spe- rimentare i diversi schemi, sia per guidare un’attività unplugged sul protocollo di Diffie- Hellman. Il lavoro presenta in dettaglio il percorso, le attività e il materiale, nonché una prima valutazione dell’intervento didattico, condotta dopo due edizioni (la prima online e la seconda in presenza)

Teaching informatics to novices: big ideas and the necessity of optimal guidance

This thesis reports on the two main areas of our research: introductory programming as the traditional way of accessing informatics and cultural teaching informatics through unconventional pathways. The research on introductory programming aims to overcome challenges in traditional programming education, thus increasing participation in informatics. Improving access to informatics enables individuals to pursue more and better professional opportunities and contribute to informatics advancements. We aimed to balance active, student-centered activities and provide optimal support to novices at their level. Inspired by Productive Failure and exploring the concept of notional machine, our work focused on developing Necessity Learning Design, a design to help novices tackle new programming concepts. Using this design, we implemented a learning sequence to introduce arrays and evaluated it in a real high-school context. The subsequent chapters discuss our experiences teaching CS1 in a remote-only scenario during the COVID-19 pandemic and our collaborative effort with primary school teachers to develop a learning module for teaching iteration using a visual programming environment. The research on teaching informatics principles through unconventional pathways, such as cryptography, aims to introduce informatics to a broader audience, particularly younger individuals that are less technical and professional-oriented. It emphasizes the importance of understanding informatics's cultural and scientific aspects to focus on the informatics societal value and its principles for active citizenship. After reflecting on computational thinking and inspired by the big ideas of science and informatics, we describe our hands-on approach to teaching cryptography in high school, which leverages its key scientific elements to emphasize its social aspects. Additionally, we present an activity for teaching public-key cryptography using graphs to explore fundamental concepts and methods in informatics and mathematics and their interdisciplinarity. In broadening the understanding of informatics, these research initiatives also aim to foster motivation and prime for more professional learning of informatics