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Better Know Cryptography History
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John Downey
September 26, 2011
Programming
1
190
Better Know Cryptography History
John Downey
September 26, 2011
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Transcript
None
¡ Used transposition ¡ Not very complex §
Most people couldn’t read anyway ¡ Caesar cipher (shift 3) § Hello § Khoor ¡ ROT-‐13
¡ A type of polyalphabetic cipher ¡ Confederacy
used during the Civil War ¡ Used a repeating key ¡ Example § ATTACKATDAWN § LEMONLEMONLE § LXFOPVEFRNHR
¡ 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
¡ 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
WXRCZTRNXZPZOLGMSUYSQLDGZVHHDTEUS MBPXCLDIGSOIWBOBPMPVDCNFIRHULLIWV TYIJMJWOLFNFPPXJIZSHRLWWGDUHVNCWK BUAIUMWECQNTVPTHZZLNVZPNPNWETIJCN JLJSUNQOFZAAHNHGRUYWBPLMRZFXFVMGI WKWMNPQVASUHCIUOMFKJEKTRGIMSATKYQ SHWSDVNAUKIWXHLFKUOTEPQECBUWKLABM AXVPJZTFMCGNZYHZGPOPWCPQUUSVUSNHO GFJREDHHSKZBNFPELMTQZMKLFLKOPDOTY ZTFALPIGWLJNPAKTJXIEMNUVKRSGNFKNM
OWHEAFYXGNXIJUFQWTOSZLGEQBKXBEMCV UTJKOWYBANQGOGAXLMCCLTXMOZTLHWYDE DMAGIEEJKRYCQGMVRGPASPJXRETHHPQUA VSDEWOVKLSFGBWOFMRJEBWBIRHCGBKMVY LTGUSTXZETGAJNYXJPQSSWYIRUDPOHCUX OMRKZ