Lecture 6 - C lass Note September 25, 2008 Public Key...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Class Note September 25, 2008 Public Key Encryption Need alternative to the symmetric key encryption - Key exchange is only possible after secure communication has been established - Number of keys needed is quadratic in the number of users Now asymmetric encryption is used instead - Use two keys - One is kept private, one is public - Reduces the number of keys needed Now the number of keys is 2*n users rather than n 2 Secret/Symmetric vs Public/Assymetric Two users one key two keys Prot. Of keys kept secret at all times one public, one private Key dist. Key exchange must Can use the public key Be done “out of Band” Speed Very fast (relative) Slow (10,000 times slower) RSA-
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Secure to this day; developed in 1978; based on a very simple principle: it is easy to multiply two numbers, but is very hard to factor a large number. On a computer, factoring a really large number (give all the divisors of a really large number). These are called one way functions. Two generate an RSA crypto system
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

Lecture 6 - C lass Note September 25, 2008 Public Key...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online