Encryption Riddles as a Tool to Motivate Students in Math Class

We will briefly introduce some methods of message encryption such as transposition cyphers, substitution cyphers, polyalphabetic cyphers or asymmetric-key cryptography and consider their applicability in school practice. We verified the applicability of this topic on a sample of 14 students of teaching within the subject-elementary number theory. We gradually gave students four riddles. Their task was to decrypt the message without knowing the key or encryption method. The e-learning environment LMS Moodle was chosen as a tool for communicaation with students about the tasks. The riddle was published in the LMS Moodle at the agreed time. The students entered the correct solutions into the forum, so it was possible to find out who solved the puzzle correctly first, and at the same time, all classmates saw this solution. During the experiment, students showed great interest in such riddles, so they were offered the opportunity to create their riddle encrypted using a different encryption method. Four students took advantage of the opportunity to create unique encryption methods, which we describe in detail in the article.