1. Firewalls and Tunneling Firewalls –Acts as a barrier against unwanted network traffic –Blocks many communication channels –Can change the design space in two ways No direct communication between the system to be integrated Parties outside the firewall are not trusted

2. Firewalls and Tunneling How to get through a firewall and why? –Tunneling Tricking the firewall into believing that traffic, which otherwise should be blocked, is actually allowed  Protocols which would be blocked are hidden under protocols that are accepted by the firewall Why  not having a direct communication channel is compounded by a necessary lack of trust on all traffic generated outside the firewall

3. SECURITY Earlier security was concerned only with physical protection (e.g locks,guards and barriers). Now in computer era security is done by using password etc.

4. Why networks need security ? Through Internet we are able to connect any where in the world, and organizations are highly dependent on networks for their daily business communication, information retrieval and data processing. So, WE NEED NETWORK SECURITY.

5. Aspect of Security Data Integrity Data Integrity Data Availability Data Availability Data Confidentiality Data Confidentiality Privacy Privacy

6. Data Interity Integrity refers to protection from change: Is the data that arrives at receiver exactly the same as the data that was sent ?

7. Data Availability Availability refers to protection against disruption of service: Does data remain accessible for legitimate uses ?

8. Data Confidentiality Confidentiality refers to protection against unauthorized data access: Is data protected against unauthorized access ?

9. Privacy Privacy refers to the ability of a sender to remain anonymous: Is the sender’s identity revealed ?

10. Types of Security Threats In general, network security threats can be classified into two categories: 1.Disruption, destruction and disaster 2.Unauthorized access

11. Encryption And Confidentiality To ensure that the content of a message remains confidential despite wiretapping, must be “Encrypted”.

12. Method for encryption The encrypt function takes two arguments: A key, k, and a message to be encrypted, M. The function an encrypted version of the message, E. E=encrypt (K, M) E=encrypt (K, M) the decrypt function reverses the mapping to produce the original message: the decrypt function reverses the mapping to produce the original message: M=decrypt (K, E) M=decrypt (K, E)

13. Digital Signatures To sign a message, the sender encrypts the message using a key known only to the sender.

14. Internet Firewall Concept This is also a encryption technology, this technology helps protect an organization’s computer and networks from unwanted ‘Internet traffic’.

15. INTERNET ORGANISATION NET FIREWALL INTERNET FIREWALL:

16. WHAT IS E-COMMERCE? E-COMMERCE CONSISTS OF TWO WORDS E & COMMERCE E-COMMERCE CONSISTS OF TWO WORDS E & COMMERCE DEFINATION: DEFINATION: “ BUYING, SELLING AND MARKETING OF PRODUCTS OR SERVICES OVER ANY ELECTRONIC DEVICE LIKE COMPUTER”

17. HOW E-COMMERCE WORKS?

18. SECURITY

19. FOR TRANSMITTING ABOVE TYPE OF DATA WE REQUIRE: THE MESSAGE SHOULD BE ACCESSED ONLY BY THE INTENDED RECEIVE THE MESSAGE SHOULD BE ACCESSED ONLY BY THE INTENDED RECEIVE OTHER, WHO CAN INTERCEPT IT ON THE NETWORK, SHOULD NOT BE ABLE SO INTERPRET THE MESSAGE OTHER, WHO CAN INTERCEPT IT ON THE NETWORK, SHOULD NOT BE ABLE SO INTERPRET THE MESSAGE THE MESSAGES SHOULD NOT BE MODIFIED DURING TRANSMISSION, EITHER INTENTIONALLY OR UNINTENTIONALLY. THE MESSAGES SHOULD NOT BE MODIFIED DURING TRANSMISSION, EITHER INTENTIONALLY OR UNINTENTIONALLY.

20. HOW WE CAN ENCRYPT THE DATA OR INFORMATION PUBLIC KEY ENCRYPTION WITH RECEIVER’S PUBLIC KEY PUBLIC KEY ENCRYPTION WITH RECEIVER’S PUBLIC KEY PUBLIC KEY ENCRYPTION WITH SENDER’S PRIVATE KEY PUBLIC KEY ENCRYPTION WITH SENDER’S PRIVATE KEY CONFIDENTIAL AND AUTHENTIC MESSAGES USING PUBLIC KEY SYSTEM CONFIDENTIAL AND AUTHENTIC MESSAGES USING PUBLIC KEY SYSTEM