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Better Know Cryptography History

John Downey
September 26, 2011

Better Know Cryptography History

John Downey

September 26, 2011
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  1. ¡  Used  transposition  
    ¡  Not  very  complex  
    §  Most  people  couldn’t  
    read  anyway  
    ¡  Caesar  cipher  (shift  3)  
    §  Hello  
    §  Khoor  
    ¡  ROT-­‐13  

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  2. ¡  A  type  of  polyalphabetic  
    cipher  
    ¡  Confederacy  used  during  
    the  Civil  War  
    ¡  Used  a  repeating  key  
    ¡  Example  
    §  ATTACKATDAWN  
    §  LEMONLEMONLE  
    §  LXFOPVEFRNHR  

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  3. ¡  Used  by  Nazi’s  during  
    World  War  2  
    ¡  Was  another  type  of  
    polyalphabetic  cipher  
    ¡  One  or  more  rotors  
    would  tweak  settings  
    ¡  Each  rotor  changed  daily  
    ¡  Allies  eventually  broke  
    the  code  

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  4. ¡  Based  on  really  hard  math  
    problems  
    ¡  One-­‐way  hash  
    §  MD5,  SHA1,  etc  
    ¡  Symmetric  cipher  
    §  Works  with  a  shared  key  
    §  DES,  Blowfish,  AES,  etc  
    ¡  Asymmetric  cipher  
    §  Works  with  public/private  
    keys  
    §  DSA,  RSA,  etc  

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  5. WXRCZTRNXZPZOLGMSUYSQLDGZVHHDTEUS
    MBPXCLDIGSOIWBOBPMPVDCNFIRHULLIWV
    TYIJMJWOLFNFPPXJIZSHRLWWGDUHVNCWK
    BUAIUMWECQNTVPTHZZLNVZPNPNWETIJCN
    JLJSUNQOFZAAHNHGRUYWBPLMRZFXFVMGI
    WKWMNPQVASUHCIUOMFKJEKTRGIMSATKYQ
    SHWSDVNAUKIWXHLFKUOTEPQECBUWKLABM
    AXVPJZTFMCGNZYHZGPOPWCPQUUSVUSNHO
    GFJREDHHSKZBNFPELMTQZMKLFLKOPDOTY
    ZTFALPIGWLJNPAKTJXIEMNUVKRSGNFKNM
    OWHEAFYXGNXIJUFQWTOSZLGEQBKXBEMCV
    UTJKOWYBANQGOGAXLMCCLTXMOZTLHWYDE
    DMAGIEEJKRYCQGMVRGPASPJXRETHHPQUA
    VSDEWOVKLSFGBWOFMRJEBWBIRHCGBKMVY
    LTGUSTXZETGAJNYXJPQSSWYIRUDPOHCUX
    OMRKZ    

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