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CIS 115

Cryptography

Message to the Class

TSTEPHAAXLISLAESCEMQIYQ

Scytale

Image Source: Wikipedia

Message to the Class

TSTEPHAAXLISLAESCEMQIYQ
T    H    I    S    I
 S    A    S    C    Y
  T    A    L    E    Q
   E    X    A    M
    P    L    E    Q

Early Ciphers

Tabula Recta

Image Source: Wikipedia

Image Source: Wikipedia


Enigma Machine

Image Source: Wikipedia

Enigma Machine Rotors

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Enigma Machine Rotors

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Enigma Machine Ratchet

Image Source: Wikipedia

Image Source: Wikipedia

Enigma Machine Plugboard

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Enigma Key

Enigma Operation

Enigma Stengths

Enigma Weaknesses

Marian Rejewski

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Cracking Enigma

Bombe

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Impact

“My own conclusion is that it shortened the war by not less than two years and probably by four years … we wouldn't in fact have been able to do the Normandy Landings, even if we had left the Mediterranean aside, until at the earliest 1946, probably a bit later.”

-Sir Harry Hinsley
British Intelligence Historian

Claude Shannon

Image Source: Wikipedia

Symmetric Key Encryption

Image Source: Wikipedia

Public Key Encryption

Image Source: Askamathematician.com

RSA Encryption

RSA Example

RSA Example

RSA Keys

Assignments

Blog 6: Computing Science & Mathematics

As we embark on reading the last textbook, it should be very obvious by now that mathematics is a core aspect of Computing Science. In fact, most Computing Science departments and disciplines have a direct foundation in the study of mathematics. Here’s a good quote summing it up from Harold Abelson: “Mathematics provides a framework for dealing precisely with notions of "what is". Computation provides a framework for dealing precisely with notions of "how to".” For this article, write about how Computing Science and Mathematics are related. (Food for thought - Read up on Theoretical Computer Science and Applied Mathematics: https://en.wikipedia.org/wiki/Theoretical_computer_science and https://en.wikipedia.org/wiki/Applied_mathematics). Things you can talk about: