# 15 - Diffie Hellman Introduction Cryptography and Protocols...

This preview shows pages 1–4. Sign up to view the full content.

Introduction Diffie – Hellman Cryptography and Protocols Andrei Bulatov

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

View Full Document
Cryptography and Protocols – Diffie – Hellman 15-2 Key Exchange Using public key cryptography is expensive. A better way is to use in it limited amount to generate a key for a private key cryptosystem If p is prime then there is a primitive root modulo p, that is a number g such that Diffie – Hellman protocol: - Alice chooses a prime q and finds a primitive root g - Alice chooses a random X from {1, …, q – 2} and sends p, q and to Bob - Bob chooses random Y from {1, …, q – 2} and sends to Alice - Alice and Bob compute (by computing and respectively. They use k as a private key } , , , , { } 1 , , 2 , 1 { 1 3 2 - = - p g g g g p K K ) (mod ˆ q g X X ) (mod ˆ q g Y Y ) (mod q g k XY X Y ˆ Y X ˆ
Cryptography and Protocols – Diffie – Hellman 15-3 Diffie – Hellman Protocol Alice Bob * p X Z * p Y Z X g Y g X Y g k ) ( = Y X g k ) ( =

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 10

15 - Diffie Hellman Introduction Cryptography and Protocols...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online