CSE 5/7353 – February 1st 2006

Public Key Cryptography

Keys

• Public Key

• Private Key

Uses

• Y = E (Pub , X)

• X = D(PRb, Y)

Uses

• Y = E (PRa , X)

• X = D(PUa, Y)

Uses

• Z = E (PRb, E((PRa , X))

• X = D(PUa, D(PRa, Y)

Algorithms

• RSA

• Elliptic Curve

• Diffie-Hellman

• DSS

Diffie-Hellman

Diffie-Hellman Example

Hashes

• Calculate hash code

• Encrypt Hash Code for Authentication.

• Message Example

Birthday Attack

Birthday Attack Math

Block Chaining

Meet in the Middle