1. Fundamentals of Network Security Ravi Mukkamala SCI 101 October 6, 2003

2. Goals Authentication: Are you who you claim to be? Authorization: Are you authorized to do this? Integrity: Is the message what the user has sent? Confidentiality: Can one read this? Availability (Denial-of-service attacks) Accountability (Non-repudiation): How can we prove that the message was indeed sent by the sender?

3. Tools Cryptography: Symmetric and asymmetric Symmetric: A single secret key for encryption and decryption Asymmetric: A key pair: Public key and private key; sender encrypts using key owner’s public key; key owner decrypts using corresponding private key

4. Tools (contd.) Encryption/Decryption algorithms Digital signatures: Sender uses private key to generate a special tag and appends to the message. Receiver cross checks the integrity by rechecking with the sender’s public key. (Third party can resolve a dispute) Message authentication code (MAC): Secret key, when applied on a message, gives MAC. The receiver can regenerate the MAC and ensure the integrity of the message Cryptographic hash functions

5. Network security

6. Network filters Firewalls Routers

7. Public-key Infrastructure CA: certificate authority RA: registration agent Issuance and revocation of certificates Trust points Certificate and path verification Delegation

8. References www.cs.odu.edu/~cs472 www.cs.odu.edu/~cs772 Network Security: Private Communications in a Public World, 2nd edition, 2002, C. Kaufman, R. Perlman, and M. Speciner, Prentice-Hall.Network Security: Private Communications in a Public World, Cryptography and Network Security: Principles and Practice (3rd Edition) by William StallingsCryptography and Network Security: Principles and Practice (3rd Edition) Hacking Exposed: Network Security Secrets & Solutions, Fourth Edition by Stuart McClure, et alHacking Exposed: Network Security Secrets & Solutions, Fourth Edition