Math Alive Lecture Notes | Cryptography : From World War II machines to unbreakable codes

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  PDF Part 1: The Hagelin Cryptograph - One of the most popular cryptographs in the 1940's and 1950's. Binary Numbers. Binary Addition. Parity Addition. HBO - Transmission of encrypted password.
• PDF Part 2: Modular arithmetic. Modular multiplication. Fermat's little theorem. Public key cryptography. The RSA algorithm.
• PDF Addendum to Part Two with Updates on RSA Challenge and Largest Known Prime (as of Feb. 1, 2009)