1. 8.4 – 8.5 Securing E-mail & Securing TCP connections with SSL By: Amanda Porter

2. 8.4 Securing E-mail 4 Layers in Protocol Stack Application Layer ▫ Email Transport Layer ▫ SSL Protocol Network Layer ▫ IPSec Link Layer ▫ IEEE 802.11

3. 8.4 Securing E-mail Why have multiple-layer security? To provide user level security It is easier to deploy security services at higher layers in protocol stack

4. 8.4 Securing E-mail 4 Security Features Confidentiality Sender Authentication Message Integrity Receiver Authentication

5. 8.4 Securing E-mail Confidentiality Public Key Cryptography ▫ RSA Symmetric Key Technology ▫ DES or AES

6. 8.4 Securing E-mail Sender Authentication & Message Integrity Without Confidentiality ▫ Digital Signatures and Message Digests

7. 8.4 Securing E-mail Sender Authentication & Message Integrity With Confidentiality

8. 8.4 Securing E-mail Pretty Good Privacy (PGP) ---BEGIN PGP SIGNED MESSAGE--- Hash: SHA1 Bob: My husband is out of town tonight. Passionately yours, Alice ---BEGIN PGP SIGNATURE--- Version: PGP 5.0 Charset: noconv yhHJRHhGJGhgg/12EpJ+lo8gE4vB3mqJhFEvZP9t6n7G6m5Gw2 ---END PGP SIGNATURE--- ---BEGIN PGP MESSAGE--- Version: PGP 5.0 u4g9fh0KJF03hjdoe./jehfiwoefwehg032rskjclnvbiol -----END PGP MESSAGE

9. 8.5 Securing TCP Connections: SSL SSL Secure Sockets Layer ▫ Enhanced version of TCP Transport Layer Security ▫ Slightly modified version of SSL (version 3) Https

10. 8.5 Securing TCP Connections: SSL Why SSL? Provides confidentiality Provides data integrity Provides server authentication

11. 8.5 Securing TCP Connections: SSL Three Phases Handshake Key Derivation Data Transfer (Connection Closure)

12. 8.5 Securing TCP Connections: SSL SSL Handshake Server authentication ▫ Master Secret (MS) ▫ Encrypted Master Secret (EMS)

13. 8.5 Securing TCP Connections: SSL SSL Key Derivation Generate Four Keys: ▫ E B = encryption ▫ M B = MAC ▫ E A = encryption ▫ M A = MAC

14. 8.5 Securing TCP Connections: SSL SSL Data Transfer Break data stream into records: DataMAC VersionLengthType Encrypted with E B

15. 8.5 Securing TCP Connections: SSL Real SSL Server authentication Negotiation: agree on crypto algorithms Establish keys Client authentication (optional)

16. 8.5 Securing TCP Connections: SSL Closing Connection TCP FIN Type field

17. Bibliography [1] J. Kurose and K. Ross, Computer Networking: A top-down approach, 5 th edition. New York: Pearson Education, Inc., 2010. [2] M.S.Bhiogade, “Secure Socket Layer”, in InSITE - “Where Parallels Intersect,” June 2002, pp. 85-90. [3]A. Weaver, “How Things Work Secure Sockets Layer,” in Computer – Innovative Technology for Computing Professionals, April 2006. [4] R. Bazile and O. Wong, “Pretty Good Privacy Network Security and Cryptography, CS682,” November 4, 2002. [5] D.V. Bhatt, S. Schulze, G.P. Hancke, L. Horvath, “Secure Internet access to gateway using secure socket layer,” in Virtual Environments, Human- Computer Interfaces and Measurement Systems, July 2003, pp. 157- 162. [6] S. Garfinkel and G. Spafford, Web Security and Commerce. Sebastopol, CA : O'Reilly & Associates, Inc., 1997. [7] A. Levi and Ç. K. Koç, “Risks in Email Security,” in Inside Risks, 2001. [8] M. Sunner, “Email Security,” in Network Security, Volume 2005, Issue 12, December 2005, pp. 4-7.