Cryptography, a key element of secure digital communication and modern online economies, relies on techniques like the RSA algorithm to ensure privacy and trust in an increasingly connected world. In 1978, Ron Rivest, Adi Shamir, and Leonard Adleman introduced their groundbreaking public-key cryptosystem, which bears their initials. The RSA algorithm nicely couples the easiness of exponentiation with the hardness of factorization of large prime numbers to guarantee that communication of sensitive information that happens in public - i.e., over internet - cannot be intercepted/disrupted in practical, real-world settings given the technology available so far.

Due to its importance regarding the security of modern internet-based communication infrastructure, the RSA algorithm is a basic section in Cryptography courses in higher education. However, the required background in number theory and the involved notation usually makes it hard for students to grasp the underlying idea and apply RSA in the context of relevant problem solving.

Motivated by these observations and with an intention to make the RSA algorithm simple for students to understand and use, we designed and implemented an online application which enables students to familiarize with concepts and the application of the RSA algorithm. Our application includes educational, training and evaluation sections presented within an elegant interface enriched with visualization features. Within the educational section, we present a comprehensive description of the RSA algorithm together with indicative examples. The training section provides the application framework and focuses on letting users familiarize with the computational blocks of the RSA algorithm; the training section can be also used as an online simulator helping students crosscheck their solutions to course exercises and problems. The evaluation section contains a test enabling students to verify their understanding and knowledge regarding the overall RSA framework. Furthermore, a calculator functionality is provided for exponentiation and modulo operations. Compared to existing relevant works, the novelty of our application mainly lies in its graphical interface and game-like nature. Extending the concept of existing approaches, like for example “RSA visual and more” and “Learn RSA Cryptography”, which focus on providing results, our application places special emphasis on assisting users to comprehend the essence of the algorithm by interacting with the whole computational procedure taking place. Graphics and visualizations aim to capture the attention of users and thus obtain their engagement in completing all available sections.

Our application is responsive and thus can be used on all user devices (smartphones, tablets, and computers) regardless of their screen size. The application has been developed using the React free and open-source front-end JavaScript library as the main development environment and Github Pages for online hosting.

Keywords: Cryptography courses, RSA public-key cryptosystem, educational and training web app, React.