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CIS 115

Lecture 17: 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

Image Source: Wikipedia

Enigma Machine Rotors

Image Source: Wikipedia

Enigma Machine Ratchet

Image Source: Wikipedia

Image Source: Wikipedia

Enigma Machine Plugboard

Image Source: Wikipedia

Enigma Key

Enigma Operation

Enigma Stengths

Enigma Weaknesses

Marian Rejewski

Image Source: Wikipedia

Cracking Enigma

Bombe

Image Source: Wikipedia

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 8: TBD

TBD