Mathematical ciphers: from Caesar to RSA

Introduction Caesar cipher Terminology and results from number theory Modular arithmetic Describing the Caesar cipher mathematically Cryptanalysis for the Caesar cipher Multiplication cipher Cryptanalysis for the multiplication cipher Multiplication-shift cipher Cryptanalysis for the multiplication-shift cipher Non-mathematical substitution ciphers Preparing to generalize Finding inverses modulo $n$ General multiplication-shift cipher Security of the general multiplication-shift cipher Introduction to the exponential cipher Deciphering the exponential cipher Cryptanalysis for the exponential cipher Mathematical basis for the exponential cipher Public key ciphers RSA cipher Signatures Security and implementation of the RSA cipher Computer programs Further reading Answers to selected exercises Index.