History of Cryptography

1. History of Cryptography http://www.cypher.com.au/crypto_history.htm

2.  2000 BC hieroglyphic inscriptions on tomb of KHNUMHOTEP II had additional symbols to confuse or obscure meaning Hieroglyphs

3. 5BC SPARTANS developed a cryptographic device to send and receive secret messages. Both sender and receiver had a cylinder A narrow strip of parchment or leather was wound around the SCYTALE and the message was written across it. Once unwound, for transport to the receiver, the tape displayed only a sequence of meaningless letters until it was re-wound onto a SCYTALE of exactly the same diameter. Transposition cypher - letters remain the same but order is changed. SCYTALE

4. 100 BC Messages encoded by substituting the letter in the text by one that is three positions to the right Used by Julius Caesar Caesar Cipher

5. 1466 Battista Alberti, Italian cypher disk Polyalphabetic Cypher

6. Mid-1500’s Blaise de Vigenere Vigenere Square Precursor to one-time pad Key repeats Broken in 1854 by Charles Babbage Also broken by Kasiski in 1863 Vigenere Square

7. 1917 British ship TELCONIA cut Germany’s transatlantic cables, forcing all international traffic to be sent via Sweden or American-owned cables All communication traffic intercepted by British British decrypted a message encrypted in the German Foreign Office code As a result, US entered the war WW I

8. Towards end of WWI Joseph Mauborgne code based on truly random keys Two identical pads printed with lines of randomly generated letters Using the Vigenere technique, each page is to be used to encrypt and decrypt ONE message and then destroyed. No useable pattern or structure within the message due to randomness of key Perfect secrecy One-Time Letter Pad (OTLP)

9. Circa 1943 The ENIGMA machine Developed by German Arthur Scherbius Patented in 1919. Lacked commercial success Adopted by the German Navy in 1926, the Army in 1928 and the Air Force in 1935 WW II

10. Enigma • An off line cypher system • A manual system • Each plaintext letter was typed on a keyboard and the resultant cyphertext letter appeared illuminated on a lamp board • Each etter was transcribed on a message pad and the procedure repeated until the message was complete. • Cyphertext message was transmitted by radio using Morse code

11. 1931 “a disgruntled German public servant allowed, for a fee, a French secret service agent to photograph two ENIGMA instruction manuals which, while non-technical, contained sufficient information to deduce the internal wiring of the machine” Breaking the Enigma

12. 1932-1933 1939 Poles broke code Poles shared blueprints with French and British Enigma

13. 1980’s Government wants key escrow encryption (CLIPPER) Designed to allow US government/law enforcement to obtain one’s secret key if they established that one was involved in illegal activities Now discredited as a US government ‘Trojan horse’ The Digital Age

14. The Digital Age • Other governments ban digital security to harass political opposition and quell dissent. • Lobby groups, conspiracy theorists, oppressed minorities, distrustful and disgruntled citizens all want encryption • Secure data transfer necessary for e-commerce

15. 1976 DES – Data Encryption Standard US National Bureau of Standards adopted an encryption algorithm that could be tested and certified DES

16. PGP • Late 1980’s • PGP – Pretty Good Privacy • Philip Zimmermann • Initially, an unlicensed implementation of RSA was used to provide key management • The IDEA algorithm was used to provide the actual data encryption layer. • Complete package was downloaded onto the internet so that it could be distributed as freeware • US government started criminal investigation under Arms Export Control Act. Later dropped.

17. 1975 Developed the concept of the asymmetric key which opened the possibility of operating a cryptosystem with a public (published) and private (secret) key. DIFFE-HELLMAN-MERKEL KEY EXCHANGE

18. 1977 Rivest, Shamir and Adleman Based on the difficulty in factoring large numbers. Private and public keys can be functions of large (300-400 digit) prime numbers. Recovering the plaintext from the public key is considered to be the equivalent to factoring the product of the two prime numbers, a major computational task RSA