1. Presentaion on ipsecurity Presentaion given by arun saraswat To lavkush sharma sir arun saraswat1

2. Outline Internetworking and Internet Protocols (Appendix 6A) IP Security Overview IP Security Architecture Authentication Header Encapsulating Security Payload Combinations of Security Associations Key Management arun saraswat2

3. 3 TCP/IP Example

4. arun saraswat4 IPv4 Header

5. arun saraswat5 IPv6 Header

6. The need...  In CERTs 2001 annual report it listed 52,000 security incidents  the most serious involving:  IP spoofing  intruders creating packets with false address then taking advantages of OS exploits  eavesdropping and sniffing  attackers listen for userids and passwords and then just walk into target systems  as a result the IAB included authentication and encryption in the next generation IP (IPv6) arun saraswat6

7. IP Security Scenario arun saraswat4

8. IP Security Overview IPSec is not a single protocol. Instead, IPSec provides a set of security algorithms plus a general framework that allows a pair of communicating entities to use whichever algorithms provide security appropriate for the communication. arun saraswat8

9. IP Security Overview Applications of IPSec ◦ Secure branch office connectivity over the Internet ◦ Secure remote access over the Internet ◦ Establsihing extranet and intranet connectivity with partners ◦ Enhancing electronic commerce security arun saraswat9

10. IP Security Architecture IPSec documents: ◦ RFC 2401: An overview of security architecture ◦ RFC 2402: Description of a packet encryption extension to IPv4 and IPv6 ◦ RFC 2406: Description of a packet emcryption extension to IPv4 and IPv6 ◦ RFC 2408: Specification of key managament capabilities arun saraswat10

11. arun saraswat11 Henric Johnson IPSec Document Overview

12. IPSec general IP Security mechanisms provides ◦ authentication ◦ confidentiality ◦ key management applicable to use over LANs, across public & private WANs, & for the Internet arun saraswat12

13. IPSec Services Two protocols are used to provide security: – Authentication Header Protocol (AH) – Encapsulation Security Payload (ESP) Services provided are: – Access control – Connectionless integrity – Data origin authentication – Rejection of replayed packets a form of partial sequence integrity – Confidentiality (encryption) – Limited traffic flow confidentiality arun saraswat13

14. Security Associations a one-way relationship between sender & receiver that affords security for traffic flow defined by 3 parameters: – Security Parameters Index (SPI) a bit string – IP Destination Address only unicast allowed could be end user, firewall, router – Security Protocol Identifier indicates if SA is AH or ESP has a number of other parameters – seq no, AH & EH info, lifetime etc have a database of Security Associations arun saraswat14

15. Transport and Tunnel Modes Both AH and ESP have two modes ◦ transport mode is used to encrypt & optionally authenticate IP data  data protected but header left in clear  can do traffic analysis but is efficient  good for ESP host to host traffic ◦ tunnel mode encrypts entire IP packet  add new header for next hop  good for VPNs, gateway to gateway security arun saraswat15

16. arun saraswat16 Transport Mode SA Tunnel Mode SA AH Authenticates IP payload and selected portions of IP header and IPv6 extension headers Authenticates entire inner IP packet plus selected portions of outer IP header ESP Encrypts IP payload and any IPv6 extesion header Encrypts inner IP packet ESP with authentication Encrypts IP payload and any IPv6 extesion header. Authenticates IP payload but no IP header Encrypts inner IP packet. Authenticates inner IP packet.

17. arun saraswat17 Before applying AH

18. arun saraswat18 Transport Mode (AH Authentication)

19. arun saraswat19 Tunnel Mode (AH Authentication)

20. arun saraswat20 Authentication Header Provides support for data integrity and authentication (MAC code) of IP packets. Guards against replay attacks.

21. arun saraswat21 Encapsulating Security Payload ESP provides confidentiality services

22. Encryption and Authentication Algorithms Encryption: ◦ Three-key triple DES ◦ RC5 ◦ IDEA ◦ Three-key triple IDEA ◦ CAST ◦ Blowfish Authentication: ◦ HMAC-MD5-96 ◦ HMAC-SHA-1-96 arun saraswat22

23. arun saraswat23 ESP Encryption and Authentication

24. arun saraswat24 ESP Encryption and Authentication

25. arun saraswat25 Combinations of Security Associations

26. arun saraswat26 Combinations of Security Associations

27. arun saraswat27 Combinations of Security Associations

28. arun saraswat28 Combinations of Security Associations

29. Key Management Two types: ◦ Manual ◦ Automated  Oakley Key Determination Protocol  Internet Security Association and Key Management Protocol (ISAKMP) arun saraswat29

30. Oakley Three authentication methods: ◦ Digital signatures ◦ Public-key encryption ◦ Symmetric-key encryption arun saraswat30

31. arun saraswat31 Henric Johnson ISAKMP

32. Summary have considered: ◦ IPSec security framework ◦ AH Protocol ◦ ESP Protocol ◦ key management & Oakley/ISAKMP arun saraswat32