@MISC{Just10diffie-hellman, author = {Mike Just}, title = {Diffie-Hellman}, year = {2010} }

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Abstract

◮ Asymmetric or public-key cryptography ◮ Originally attributed to Diffie and Hellman in 1975, but later discovered in British classified work of James Ellis in 1971 ◮ Basic idea involves altering traditional symmetry of cryptographic protocols to convey additional info in a public key. The message sender uses this public key to convey a secret message to the receipient, without requiring a secure channel to share key information. ◮ Traditionally presented as a means of encrypting messages. In practice today, public key algorithms are used to exchange symmetric keys ◮ Public keys are key encrypting keys ◮ Symmetric keys are data encryptingn keys ◮ Public keys also used to provide integrity through digital signatures (later lecture) Prime numbers ◮ A natural number p ≥ 2 is prime if 1 and p are its only positive divisors. Prime numbers ◮ A natural number p ≥ 2 is prime if 1 and p are its only positive divisors. ◮ For x ≥ 17, then π(x), the number of primes less than or equal to x, is approximated by: x ln x < π(x) < 1.25506 x ln xPrime numbers ◮ A natural number p ≥ 2 is prime if 1 and p are its only positive divisors. ◮ For x ≥ 17, then π(x), the number of primes less than or equal to x, is approximated by: x ln x