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Introduction to Cryptography  Paul Krzyzanowski [email_address] [email_address] Distributed Systems Except as otherwise noted, the content of this presentation is licensed under the Creative Commons Attribution 2.5 License.
Ngywioggazhon Pystemp Auesfnsicutiwf & Moiiunocaiwn Piqtoaoyp
Cryptographic Systems Authentication & Communication Protocols
cryptography κρυπός hidden γραφία writing A secret manner of writing, … Generally, the art of writing or solving ciphers.  —  Oxford English Dictionary
cryptology κρυπός hidden λογια speaking 1967  D. Kahn,  Codebreakers  p. xvi, Cryptology is the science that embraces cryptography and cryptanalysis, but the term ‘cryptology’ sometimes loosely designates the entire dual field of both rendering signals secure and extracting information from them.  —  Oxford English Dictionary
Cryptography    Security ,[object Object],[object Object]
Terms ,[object Object],[object Object],[object Object],[object Object],[object Object]
Terms: types of ciphers ,[object Object],[object Object],[object Object]
Restricted cipher ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
The key BTW, the above is a  bump key . See http://en.wikipedia.org/wiki/Lock_bumping.
The key Source: en.wikipedia.org/wiki/Pin_tumbler_lock
The key Source: en.wikipedia.org/wiki/Pin_tumbler_lock
The key ,[object Object],[object Object],[object Object],[object Object],Source: en.wikipedia.org/wiki/Pin_tumbler_lock
Symmetric algorithm ,[object Object],[object Object],[object Object]
Public key algorithm ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
McCarthy’s puzzle (1958) ,[object Object],[object Object],[object Object],[object Object],[object Object]
McCarthy’s puzzle ,[object Object],[object Object],[object Object]
Solution to McCarthy’s puzzle ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
One-way functions ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
McCarthy’s puzzle example ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],110525308948445338
More terms ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
More terms ,[object Object],[object Object],[object Object],[object Object]
Yet another term ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Cryptography: what is it good for? ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Cryptographic toolbox ,[object Object],[object Object],[object Object],[object Object]
Classic Cryptosystems
Substitution Ciphers
Cæsar cipher ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Cæsar cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher shift alphabet by n (6) A B C D E F G H I J K L M N O P Q R S T U V W X Y Z U V W X Y Z A B C D E F G H I J K L M N O P Q R S T
Cæsar cipher MY CAT HAS FLEAS A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS G A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GS A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GSW A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GSWU A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GSWUN A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GSWUNB A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GSWUNBU A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GSWUNBUM A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GSWUNBUMZ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GSWUNBUMZF A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GSWUNBUMZFY A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GSWUNBUMZFYU A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher MY CAT HAS FLEAS GSWUNBMUFZYUM A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Cæsar cipher ,[object Object],[object Object],MY CAT HAS FLEAS GSWUNBMUFZYUM A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Ancient Hebrew variant  (ATBASH) ,[object Object],[object Object],MY CAT HAS FLEAS NBXZGSZHUOVZH A B C D E F G H I J K L M N O P Q R S T U V W X Y Z T S R Q P O N M L K J I H G F E D C B A Z Y X W V U
Substitution cipher ,[object Object],[object Object],MY CAT HAS FLEAS IVSMXAMBQCLMB A B C D E F G H I J K L M N O P Q R S T U V W X Y Z E A J T N C I F Z W O Y B X G K U D V H M P S R L Q
Substitution cipher ,[object Object],[object Object],[object Object]
Statistical Analysis ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Polyalphabetic ciphers ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],encrypt: A  J decrypt: J   A A J B M C Q D S Z G Y P
Vigenère polyalphabetic cipher ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T A B C D E F G H I J K L M N O P Q R S T B C D E F G H I J K L M N O P Q R S T U C D E F G H I J K L M N O P Q R S T U V D E F G H I J K L M N O P Q R S T U V W E F G H I J K L M N O P Q R S T U V W X F G H I J K L M N O P Q R S T U V W X Y plaintext letter keytext letter ciphertext letter
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS R
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS R Y
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY   E
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY E E
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY   EE Y
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY   EEY  H
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY   EEY H C
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY   EEY HC W
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY   EEY HCW  K
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY   EEY HCW K L
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY   EEY HCW KL G
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY   EEY HCW KLG E
Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY   EEY HCW KLGE X
Vigenère polyalphabetic cipher "The rebels reposed their major trust, however, in the Vigenere, sometimes using it in the form of a brass cipher disc. In theory, it was an excellent choice, for so far as the South knew the cipher was unbreakable. In practice, it proved a dismal failure. For one thing, transmission errors that added or subtracted a letter ... unmeshed the key from the cipher and caused no end of difficulty. Once Major Cunningham of General Kirby-Smith's staff tried for twelve hours to decipher a garbled message; he finally gave up in disgust and galloped around the Union flank to the sender to find out what it said." http://rz1.razorpoint.com/index.html
Transposition Ciphers
Transposition ciphers ,[object Object],[object Object],[object Object]
Transposition ciphers: staff cipher MYCATHASFLEAS MYC HAS EAS MHE M H E
Transposition ciphers: staff cipher MYCATHASFLEAS MYC HAS EAS MHE YAA Y A A
Transposition ciphers: staff cipher MYCATHASFLEAS MYC HAS EAS MHE YAA CSS C S S
Transposition ciphers: staff cipher MYCATHASFLEAS CAT SFL S xy MHE YAA CSS AFx A F x Pad out the text. This is a  block cipher  versus a  stream cipher
Transposition ciphers: staff cipher MYCATHASFLEAS CAT SFL Sxy MHE YAA CSS Afx TLy T L y
Transposition cipher ,[object Object],[object Object],[object Object],M Y C A T H A S F L E A S x y z MYCATHASFLEAS
Transposition cipher ,[object Object],[object Object],[object Object],M Y C A T H A S F L E A S x y z MYCATHASFLEAS MTFS
Transposition cipher ,[object Object],[object Object],[object Object],M Y C A T H A S F L E A S x y z MYCATHASFLEAS MTFSYHLx
Transposition cipher ,[object Object],[object Object],[object Object],M Y C A T H A S F L E A S x y z MYCATHASFLEAS MTFSYHLxCAEy
Transposition cipher ,[object Object],[object Object],[object Object],M Y C A T H A S F L E A S x y z MYCATHASFLEAS MTFSYHLxCAEyASAz
Transposition cipher with key ,[object Object],[object Object],Key:  3 1 4 2   M Y C A T H A S   F L E A   S x y z MYCATHASFLEAS
Transposition cipher with key ,[object Object],[object Object],Key:  3 1 4 2   M Y C A T H A S   F L E A   S x y z YHLx YHLx MYCATHASFLEAS
Transposition cipher with key ,[object Object],[object Object],Key:  3 1 4 2   M Y C A T H A S   F L E A   S x y z ASAz YHLxASAz MYCATHASFLEAS
Transposition cipher with key ,[object Object],[object Object],Key:  3 1 4 2   M Y C A T H A S   F L E A   S x y z MTFS YHLxASAzMTFS MYCATHASFLEAS
Transposition cipher with key ,[object Object],[object Object],Key:  3 1 4 2   M Y C A T H A S   F L E A   S x y z CAEy YHLxASAzMTFSCAEy MYCATHASFLEAS
Transposition cipher with key ,[object Object],[object Object],Key:  3 1 4 2   M Y C A T H A S   F L E A   S x y z YHLxASAzMTFSCAEY MYCATHASFLEAS
Combined ciphers ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Electro-mechanical cryptographic engines
Rotor machines ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Rotor machines ,[object Object],[object Object],[object Object],[object Object],A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Single cylinder rotor machine A B C D E F G H I J K L M  N  O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S  T  U V W X Y Z A B C D E F G H I J K L  M  N O P Q R S T U V W X Y Z G V I L C M B Q F K D O  S  P Z H R E U Z N X A T W J  A B C D E F G H I J K L M  N  O P Q R S T U V W X Y Z K H W J M D N C R G L E P  T  Q Z I S F V A O Y B U X  rotate A B C D E F G H I J K L  M  N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R  S  T U V W X Y Z
Single cylinder rotor machine A B C D E F G H I J K L  M  N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R  S  T U V W X Y Z MY CAT HAS FLEAS S
Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X  Y  Z A B C D E F G H I J K L M N O P Q R S T  U  V W X Y Z MY CAT HAS FLEAS S U
Single cylinder rotor machine A B  C  D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H  I  J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SU I
Single cylinder rotor machine A  B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T  U  V W X Y Z MY CAT HAS FLEAS SUI U
Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S  T  U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U  V  W X Y Z MY CAT HAS FLEAS SUIU V
Single cylinder rotor machine A B C D E F G  H  I J K L M N O P Q R S T U V W X Y Z A  B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUV A
Single cylinder rotor machine A  B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X  Y  Z MY CAT HAS FLEAS SUIUVA Y
Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R  S  T U V W X Y Z A B C D E F G H I J K L M N  O  P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVAY O
Single cylinder rotor machine A B C D E  F  G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H  I  J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVAYO I
Single cylinder rotor machine A B C D E F G H I J K  L  M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M  N  O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVAYOI N
Single cylinder rotor machine A B C D  E  F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J  K  L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVAYOIN K
Single cylinder rotor machine A  B C D E F G H I J K L M N O P Q R S T U V W X Y Z A  B  C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVAYOINK B
Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R  S  T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X  Y  Z MY CAT HAS FLEAS SUIUVAYOINKB Y
Multi-cylinder rotor machines ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Enigma ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Enigma Keyboard (input) Glowlamps (results) Plugboard Rotors Reflector
One-time pads ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
One-time pads ,[object Object],[object Object],[object Object],[object Object],M + K mod 26 = W Y + W mod 26 = U C + X mod 26 = Z A + O mod 26 = O T + P mod 26 = I H + W mod 26 = D A + M mod 26 = M S + A mod 26 = S F + E mod 26 = J L + L mod 26 = W E + G mod 26 = K A + H mod 26 = H S + W mod 26 = O
One-time pads ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],W - D mod 26 = W U - N mod 26 = U Z - V mod 26 = Z O - L mod 26 = O I - U mod 26 = I D - X mod 26 = D M - E mod 26 = M S - A mod 26 = S J - C mod 26 = J W - W mod 26 = W K - V mod 26 = K H - S mod 26 = H O - Q mod 26 = O
One-time pads ,[object Object],[object Object],[object Object],[object Object]
One-time pads ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Digression: random numbers ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Computer Cryptography
DES ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
DES 64 bit plaintext block initial permutation, IP left half, L 1 right half, R 0 f R 1  = L 0     f(R 0 , K 1 ) L 1 = R 0 K 1 16 rounds L 15 = R 14 R 15  = L 14     f(R 14 , K 15 ) 48-bit subkey permuted from key f L 16  = R 15 R 16  = L 15     f(R 15 , K 16 ) K 16 final permutation, IP -1 64 bit ciphertext block
DES:  f DATA: right 32 bits KEY: 56 bits DATA: left 32 bits New DATA: right 32 bits 48 bits 48 bits S S S S S S S S
DES: S-boxes ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Is DES secure? ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
The power of 2 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Increasing The Key ,[object Object],[object Object],[object Object],[object Object]
Double DES ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Triple DES ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Triple DES ,[object Object],[object Object],[object Object],[object Object],[object Object]
Popular symmetric algorithms ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
AES  ,[object Object],[object Object],http://csrc.nist.gov/encryption/aes/
The end.

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Cryptography (Distributed computing)

  • 1. Introduction to Cryptography Paul Krzyzanowski [email_address] [email_address] Distributed Systems Except as otherwise noted, the content of this presentation is licensed under the Creative Commons Attribution 2.5 License.
  • 2. Ngywioggazhon Pystemp Auesfnsicutiwf & Moiiunocaiwn Piqtoaoyp
  • 3. Cryptographic Systems Authentication & Communication Protocols
  • 4. cryptography κρυπός hidden γραφία writing A secret manner of writing, … Generally, the art of writing or solving ciphers. — Oxford English Dictionary
  • 5. cryptology κρυπός hidden λογια speaking 1967 D. Kahn, Codebreakers p. xvi, Cryptology is the science that embraces cryptography and cryptanalysis, but the term ‘cryptology’ sometimes loosely designates the entire dual field of both rendering signals secure and extracting information from them. — Oxford English Dictionary
  • 6.
  • 7.
  • 8.
  • 9.
  • 10. The key BTW, the above is a bump key . See http://en.wikipedia.org/wiki/Lock_bumping.
  • 11. The key Source: en.wikipedia.org/wiki/Pin_tumbler_lock
  • 12. The key Source: en.wikipedia.org/wiki/Pin_tumbler_lock
  • 13.
  • 14.
  • 15.
  • 16.
  • 17.
  • 18.
  • 19.
  • 20.
  • 21.
  • 22.
  • 23.
  • 24.
  • 25.
  • 28.
  • 29. Cæsar cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 30. Cæsar cipher shift alphabet by n (6) A B C D E F G H I J K L M N O P Q R S T U V W X Y Z U V W X Y Z A B C D E F G H I J K L M N O P Q R S T
  • 31. Cæsar cipher MY CAT HAS FLEAS A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 32. Cæsar cipher MY CAT HAS FLEAS G A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 33. Cæsar cipher MY CAT HAS FLEAS GS A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 34. Cæsar cipher MY CAT HAS FLEAS GSW A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 35. Cæsar cipher MY CAT HAS FLEAS GSWU A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 36. Cæsar cipher MY CAT HAS FLEAS GSWUN A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 37. Cæsar cipher MY CAT HAS FLEAS GSWUNB A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 38. Cæsar cipher MY CAT HAS FLEAS GSWUNBU A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 39. Cæsar cipher MY CAT HAS FLEAS GSWUNBUM A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 40. Cæsar cipher MY CAT HAS FLEAS GSWUNBUMZ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 41. Cæsar cipher MY CAT HAS FLEAS GSWUNBUMZF A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 42. Cæsar cipher MY CAT HAS FLEAS GSWUNBUMZFY A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 43. Cæsar cipher MY CAT HAS FLEAS GSWUNBUMZFYU A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 44. Cæsar cipher MY CAT HAS FLEAS GSWUNBMUFZYUM A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 45.
  • 46.
  • 47.
  • 48.
  • 49.
  • 50.
  • 51.
  • 52. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T A B C D E F G H I J K L M N O P Q R S T B C D E F G H I J K L M N O P Q R S T U C D E F G H I J K L M N O P Q R S T U V D E F G H I J K L M N O P Q R S T U V W E F G H I J K L M N O P Q R S T U V W X F G H I J K L M N O P Q R S T U V W X Y plaintext letter keytext letter ciphertext letter
  • 53. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS R
  • 54. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS R Y
  • 55. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY E
  • 56. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY E E
  • 57. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY EE Y
  • 58. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY EEY H
  • 59. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY EEY H C
  • 60. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY EEY HC W
  • 61. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY EEY HCW K
  • 62. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY EEY HCW K L
  • 63. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY EEY HCW KL G
  • 64. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY EEY HCW KLG E
  • 65. Vigenère polyalphabetic cipher A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z FA CEF ACE FACEF MY CAT HAS FLEAS RY EEY HCW KLGE X
  • 66. Vigenère polyalphabetic cipher "The rebels reposed their major trust, however, in the Vigenere, sometimes using it in the form of a brass cipher disc. In theory, it was an excellent choice, for so far as the South knew the cipher was unbreakable. In practice, it proved a dismal failure. For one thing, transmission errors that added or subtracted a letter ... unmeshed the key from the cipher and caused no end of difficulty. Once Major Cunningham of General Kirby-Smith's staff tried for twelve hours to decipher a garbled message; he finally gave up in disgust and galloped around the Union flank to the sender to find out what it said." http://rz1.razorpoint.com/index.html
  • 68.
  • 69. Transposition ciphers: staff cipher MYCATHASFLEAS MYC HAS EAS MHE M H E
  • 70. Transposition ciphers: staff cipher MYCATHASFLEAS MYC HAS EAS MHE YAA Y A A
  • 71. Transposition ciphers: staff cipher MYCATHASFLEAS MYC HAS EAS MHE YAA CSS C S S
  • 72. Transposition ciphers: staff cipher MYCATHASFLEAS CAT SFL S xy MHE YAA CSS AFx A F x Pad out the text. This is a block cipher versus a stream cipher
  • 73. Transposition ciphers: staff cipher MYCATHASFLEAS CAT SFL Sxy MHE YAA CSS Afx TLy T L y
  • 74.
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  • 89. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z G V I L C M B Q F K D O S P Z H R E U Z N X A T W J A B C D E F G H I J K L M N O P Q R S T U V W X Y Z K H W J M D N C R G L E P T Q Z I S F V A O Y B U X rotate A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • 90. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS S
  • 91. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS S U
  • 92. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SU I
  • 93. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUI U
  • 94. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIU V
  • 95. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUV A
  • 96. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVA Y
  • 97. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVAY O
  • 98. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVAYO I
  • 99. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVAYOI N
  • 100. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVAYOIN K
  • 101. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVAYOINK B
  • 102. Single cylinder rotor machine A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z MY CAT HAS FLEAS SUIUVAYOINKB Y
  • 103.
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  • 105. Enigma Keyboard (input) Glowlamps (results) Plugboard Rotors Reflector
  • 106.
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  • 114. DES 64 bit plaintext block initial permutation, IP left half, L 1 right half, R 0 f R 1 = L 0  f(R 0 , K 1 ) L 1 = R 0 K 1 16 rounds L 15 = R 14 R 15 = L 14  f(R 14 , K 15 ) 48-bit subkey permuted from key f L 16 = R 15 R 16 = L 15  f(R 15 , K 16 ) K 16 final permutation, IP -1 64 bit ciphertext block
  • 115. DES: f DATA: right 32 bits KEY: 56 bits DATA: left 32 bits New DATA: right 32 bits 48 bits 48 bits S S S S S S S S
  • 116.
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