Network Security Cryptography & Steganograpy

By

Nikhil

A Security History Of The WorldGoths,vandals,huns

Burglar by hacker

Why do we need security?

Introduction

●What is Network Security:

Network security define the protection, safe guarding of the computers in the network by using security tools.

Who is vulnerable?

•Financial institutions and banks

•Internet service providers Government and Defense services

•Multinational corporations

ANYONE ON THE NETWORK

Common security attacks and their

countermeasures

• Finding a way into the network– Firewalls

• TCP hijacking– IPSec

• Packet sniffing– Encryption (SSH, SSL, HTTPS)

Firewalls

TCP Attacks

• Say hello to sandy, Bob and Sam

TCP Attacks• Sandy and Bob have an established TCP

connection

TCP Attacks

• Sam lies on the path between Sandy and Bob on the network– He can intercept all of their packets

TCP Attacks

• First, Sam must drop all of Sandy’s packets since they must not be delivered to Bob (why?)

Packets

The Void

TCP Attacks

• How do we prevent this?

• IPSec– Provides source authentication, so Sam

cannot pretend to be Sandy– Encrypts data before transport, so Sam

cannot talk to Bob without knowing what the session key is :-

Types of Secret Writing

Secret writing

Cryptography Steganography

Cryptography“Strategy without tactics is the slowest route to victory. Tactics without strategy is the noise before defeat.”

Sun Tzu 

Cryptography

example :-

Benefits of Cryptographic Technologies

• Data secrecy

• Data integrity

• Authentication of message originator

• Electronic certification and digital signature

• Non-repudiation

Potential Problems with Cryptographic Technologies?

• False sense of security if badly implemented

• Government regulation of cryptographic technologies/export restrictions

• Encryption prohibited in some countries

Steganography

•Steganography –covered writing – is an art of hiding information

•Popular contemporary Steganography technologies hide information in images

How Secure are Today’s

• Encryption does not guarantee security!• Many ways to beat a crypto system NOT

dependent on cryptanalysis, such as:– Viruses, worms, hackers, etc.– Unauthorized physical access to secret keys

• Cryptography is only one of the elements of comprehensive computer security• high overhead to hide relatively few info bits

Technologies

Conclusion