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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