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Chapter 3 Simple Cryptography
Objectives
Investigate substitution ciphers
Investigate other shared-key cryptosystems
Implement some cryptographic algorithms
Investigate public key cryptography
As long as their has been a need to communicate information, there has been a desire to hide that communication from unintended recipients.
Cryptography , loosely translated from the Greek roots as
secret writing , is the study and implementation of secure communication in the possible presence of adversaries. We will start by extending our investigation of permutations into their application to cryptography before moving through more complicated permutation-based cryptography. Then we will deviate into other cryptosystems not based upon permutations, revisiting the idea of public key cryptography introduced in
Section 1.2 .
