Crypto

1
History of Cryptography

• Adam Goodbar
• Clemson University
• April, 2007

2
Origins of Cryptography

• Thought that the earliest form of cryptography
  was in the Egyptian town of Menet Khufu
• The hieroglyphics on the tomb of nobleman
  KHNUMHOTEP II contained unusual symbols, used to
  obscure the meaning of the inscriptions.

3
Origins of Cryptography

• The Spartans, in 5 BC, developed a device called
  a Scytale.
• A messenger would carry a strip of parchment,
  which was meaningless until it was wrapped around
  a Scytale of the same dyameter.
• Was a type of Transposition Cypher.

4
Origins of Cryptography

• Caesar Shift Cipher
• Each letter was substituted by shifting n places
• Only 25 possible ciphers.
• Substitution Based on Key Phrase
• Key consists of Phrases Letters (Unique),
  followed by the rest of the alphabet.
• THIS IS ALICE AND BOBS KEY
• THISALCENDBOKY-FGJMPQRUVWXZ
• 26! Possible ciphers.

5
Cryptanalysis and World War I - The Zimmermann
Telegram

• The Telegram from Germany, to Mexico, proposed a
  German supported offensive by Mexico on the
  United States, if the US should attack Germany
  and become involved in WWI.
• The breaking of this telegram by Room 40 of
  British Naval Intelligence, and the passing of
  the telegram to the US, helped prompt the USs
  entry into World War I.

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7
GCHQ

• During WWI, the British Army had a separate
  SIGINT division from the British Navy.
• The Navys SIGINT division was the famous Room
  40, or NID25
• After WWI, it was proposed that a peacetime
  codebreaking division be created
• The Government Communications Headquarters was
  created

8
GCHQ

• Based out of Bletchley Park, and famous for
  breaking German Enigma codes.
• Pre WWII, was a very small department.
• By 1940, was attacking codes of 26 countries and
  over 150 diplomatic cryptosystems
• Discussed in Neal Stephensons Cryptonomicon
• Great Book! Takes many historical liberties
  however.

9
World War II Cryptography

• Most Famous example of Cryptography in World War
  II was the German Enigma.
• Made use of Rotors and Plugboards
• One or more of the rotors moved after each key
  press, depending on the settings.
• Created a changing substitution cypher, or a
  polyalphabetic substitution cypher.

10
Cryptanalysis and World War II -

• Britain used the term Ultra to describe
  intelligence from the cryptanalysis, specifically
  resulting from Enigmas.
• Britain's top military officers were told they
  must never reveal that the German Enigma code had
  been broken because it would give the defeated
  enemy the chance to say they were not well and
  fairly beaten by Gp Capt Winterbotham
• Gp Capt Winterbotham was the first to break this
  rule, in 1974.

11
Current Day Cryptography - Diffie-Hellman key
exchange

• Produced by Whitfield Diffie and Martin Hellman
  in 1976
• Later discovered that a similar method had been
  developed by the GCHQ (The British SIGINT
  agency), in 1973, but was kept classified until
  1997
• D-H developed the method independently.

12
Whitfield Diffie

• Received a BS from MIT in 1965, and awarded a
  Doctorate in Technical Sciences (Honoris Causa)
  from the Swiss Federal Institute of Technology in
  1992
• Joined Sun Microsystems in 1991, as a
  Distinguished Engineer.
• Currently still a Sun employee, serving as VP,
  Sun Fellow, and Chief Security Officer

13
Martin Hellman

• Earned his Bachelors of Science from New York
  University in 1966, and a Masters in 1967 and PhD
  in 1969 from Stanford University, in Electrical
  Engineering.
• Assistant Professor at MIT from 1969 1971
• Became a Stanford Professor in 1971, until 1966,
  when he became Professor Emeritus

14
Current day Cryptography RSA Encryption

• Developed by Ron Rivest, Adi Shamir, and Leonard
  Adleman
• Type of Public Key Encryption
• Later discovered that a similar method had been
  developed by the GCHQ (The British SIGINT
  agency), in 1973, but was kept classified until
  1997

15
Ron Rivest

• Earned a BS in Mathematics from Yale in 1969, and
  a Ph. D in Computer Science from Stanford
  University in 1974.
• Also authored RC2, RC4, RC5, and co-invented RC6
• Author of MD2, MD4, and M5 Cryptographic Hash
  Functions

16
ThreeBallot

• The System has two goals
• Have voter's votes be "secret ballot" so that
  nobody can know how anyone voted (not even if the
  voter wants to tell them) and hence nobody could
  bribe or coerce you to vote some way, and you
  could not sell your vote.
• Have the election be secure and verifiable so
  that we could all be confident that nobody voted
  more than once, no votes were inserted, deleted,
  or altered, only authorized voters voted, and the
  results were computed correctly from those
  votes.
• (From RangeVoting.org)

17
ThreeBallot

• Trouble is, these two desires seem incompatible.
  It is trivial to get secure elections if the
  ballots are not secret just publicize every
  voter-vote pair to make it trivial to verify that
  everybody voted as they said they did (or didn't)
  and the ballots were tallied correctly. But then
  it'd also be trivial to coerce voters, rather
  undermining "democracy. (From RangeVoting.org)
• Immediately put in the Public Domain by Rivest.

18
ThreeBallot

• From Website
• Coercer "I demand you vote AGAINST Bush. And
  bring me a receipt saying 'AGAINST BUSH' on it."
• You Yes, boss!
• Coercer Very good. But wait, how do I know you
  did not also vote FOR Bush twice (and also both
  FOR and AGAINST Nader) and thus in total really
  voted for Bush?
• You You don't.
• Coercer (foiled again).

19
Adi Shamir

• Received a BS in Mathematics from Tel Aviv
  University in 1973.
• MS and Ph.D from the Weizmann Institute in
  1975/1977
• Researched at MIT from 1977 1980.
• Then returned as a faculty member at the Weizmann
  Institute
• Discovered Differential Cryptanalysis, used for
  attacking Block Cyphers

20
Leonard Adleman

• Attended UC Berkley, receiving his BA in
  Mathematics in 1968, and then his Ph.D in EECS
  1976.
• Heavy research in DNA computing.
• Published a paper in 1994, entitled Molecular
  Computation of Solutions To Combinatorial
  Problems
• Solved a 7 node Hamiltonian graph using DNA
  computation

21
Current day Cryptography DES

• Symmetric Key Algorithm.
• DES Uses a 56-bit key, so 256 possible keys.
• Over 72 quadrillion keys!
• Even with all these keys, still susceptible to
  brute force attacks.
• It is known that the NSA encouraged, if not
  persuaded, IBM to reduce the key size from 128 to
  64 bits, and from there to 56 bits this is often
  taken as an indication that the NSA possessed
  enough computer power to break keys of this
  length even in the mid-1970s. (Wikipedia)

22
Deep Crack

• Built in 1998, for a cost of 250,000
• Able to brute force a key within a day.
• Used to win RSAs Security DES Challenge III

23
COPACOBANA(Cost-Optimized PArallel COde Breaker)

• Cost of 10,000

• 120 FPGA Processors on 20 DIMM modules

24
References

• Ron Rivest's "3ballot" scheme for
  cryptographically-secure voting without
  cryptography! and the "BOFFO" plan, Warren D.
  Smith, http//rangevoting.org/Rivest3B.html
• http//www.telegraph.co.uk/news/main.jhtml?xml/ne
  ws/2006/06/22/nenigma22.xmlsSheet/news/2006/06/2
  2/ixuknews.html
• Wikipedia (As a starting point ?)
• http//www.cypher.com.au/crypto_history.htm