By hiding messages in shapes, gibberish, and number codes, cryptography has allowed people, from the time of the ancient Greeks through today, to safely transmit secrets. Court intrigue, star-crossed love, and war have all benefited immensely from this method of communication. These days, cryptographers have traded the cipher disk for the computer screen, but cryptography still influences our life in covert ways. By harnessing statistics, abstract algebra, and other branches of mathematics, cryptography lets us breathe easier when we go to an ATM, create a password for our computer, or send money electronically.
The Secrets of Telling Secrets (Grades 4 through 12)
Students are introduced to the substitution cipher, which hides messages by replacing letters or groups of letters with other letters or groups of letters. Working with their classmates, students practice making and breaking different ciphers.
Keeping Secrets in Public (Grades 11 and 12)
Students are introduced to public key cryptography, which allows the public to encrypt but not decrypt, and only gives select individuals the decryption key. This type of cryptography solves the problem of passing along the key easily and securely. Using arithmetic and network graphs, students will explore this complex and fun type of secret-keeping!