11. Security

11. Security - 1 Network Security Communication Networks ©...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full Document Right Arrow Icon

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

View Full Document Right Arrow Icon

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

View Full Document Right Arrow Icon

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

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

Unformatted text preview: 1 Network Security Communication Networks © Kang Xi, Polytechnic Institute of NYU 2 What do We Need? ¡ Confidentiality ¢ You are downloading your credit card statement, if Mr. Hacker captures your packets…. ¡ Integrity ¢ How to detect a message has been modified… ¡ Availability ¢ Available to authorized parties ¡ Authenticity ¢ You have a link to your bank, how do you know it is not Mr. Phisher’s bank? Encryption ¡ Make the content of a message unreadable to anyone except those possessing special knowledge ¡ Special knowledge often consists of a secret key and decryption method Communication Networks © Kang Xi, Polytechnic Institute of NYU 3 Communication Networks © Kang Xi, Polytechnic Institute of NYU 4 Symmetric Encryption ¡ Sender and receiver ¢ Share the same Secret Key ¡ Sender ¢ Encryption algorithm( Plaintext, Key ) Î Ciphertext ¡ Receiver ¢ Decryption algorithm( Ciphertext, Key ) Î Plaintext Communication Networks © Kang Xi, Polytechnic Institute of NYU 5 Example ¡ Algorithm: XOR ¡ Plaintext: 1101 1001 1111 ¡ Key: 1001 ¡ Cyphertext: 0100 0000 0110 ¡ How to attack for the key? Communication Networks © Kang Xi, Polytechnic Institute of NYU 6 Cryptanalysis ¡ Know both plaintext and cyphertext ¡ Exploit algorithm characteristics for keys ¡ Example: ¢ Plaintext: 1101 1001 1111 ¢ Cyphertext: 0100 0000 0110 ¢ XOR: 1001 1001 1001 Communication Networks © Kang Xi, Polytechnic Institute of NYU 7 Brute-force ¡ Try all possible keys on cyphertext to get an intelligible plaintext Communication Networks © Kang Xi, Polytechnic Institute of NYU 8 Requirements for Strong Encryption...
View Full Document

{[ snackBarMessage ]}

Page1 / 27

11. Security - 1 Network Security Communication Networks ©...

This preview shows document pages 1 - 9. Sign up to view the full document.

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