NETWORK SECURITY Cryptography By: Abdulmalik Kohaji

OUTLINE Network Security - Introduction - Networks - Network Security - Firewalls - Cryptography - Conclusion

Introduction Network Security Information Growth Networks Growth Network Security Growth

Networks General Concepts

What is Network? Network Security: Networks Hardware and Devices Software and Systems Mediums Data

Communication Media Network Security: Networks Wired Twisted Pair Coaxial Cable ITU-T G.hn Optical Fiber Wireless Microwaves Radio Waves Spread Spectrum Infrared

Networks Security

Overview Network Security: Network Security Purpose Responsibility Industry Hardware & Software Development Information

Information Security Network Security: Network Security Why do people want to secure networks? Information means power

Rules of Security Network Security: Network Security - Integrity: all of the information stored is always correct and protected against corruption as well as willful alterations. - Confidentiality: the ability to share information on the network with intended people only. - Availability of information

Threats Network Security: Network Security Type Description Example DoS (Denial-of-Service) The nastiest, and most difficult to address. Easy to launch, difficult to track. Send more requests to the machine than it can handle. Unauthorized Access access some restricted resources Access a website database without permission

Sources of Threats Network Security: Network Security Internal Systematic Users External

Lessons Learned Network Security: Network Security Backups Don't put all the data on one place Don’t put the restricted data on the network if not needed Avoid systems with single points of failure Always update the security system and policy Stay current with relevant operating system patches Watch for relevant security advisories

Firewalls

Definition Network Security: Firewalls Control income and outcome Checkpoint Internetworking Internal Network Assumption

Terms Network Security: Firewalls Router Connecting networks together Manage the traffic Access Control List Lists employed to limit the sorts of packets allowed to come in and go out Demilitarized Zone

Types Network Security: Firewalls Application Gateway Run App Layer as Proxy Server The most secure but slowest Packet Filtering ACL turned on in the router Less overhead Hybrid Systems High Security of AG Speed and Flexibility of PF

Cryptography

What ? Network Security: Cryptography Original Word When it was used? How it was used? Why it is used for networks now?

Terms Network Security: Cryptography Cryptology Encoding Decoding Encryption Key Code-Book Cryptanalysis Ciphertext Plaintext

Security Functions Network Security: Cryptography Authentication: The process of proving one's identity Privacy/confidentiality: Ensuring that the message is available only to the intended receiver. Integrity: Assuring the receiver has not been altered in any way from the original message. Non-repudiation: an approval that the message is really sent by the sender

Differences Network Security: Cryptography WHAT IS THE DIFFERENCE BETWEEN NETWORK SECURITY AND CRYPTOGRAPHY? Network Security Firewalls Auditing Intrusion Detection Systems (IDS) Encrypting Messages & Authentication Cryptography

Algorithms Network Security: Cryptography - Secret Key Cryptography (SKC): Uses a single key for both encryption and decryption Public Key Cryptography (PKC): Uses one key for encryption and another for decryption Hash Functions: Uses a mathematical transformation to irreversibly "encrypt" information

SKC Network Security: Cryptography A single key is used for both encryption and decryption The key must be known to the sender and the receiver The biggest difficulty is the distribution of the key

PKC Network Security: Cryptography Two parties Secure communication Non-secure communications channel Without having to share a secret key The sender’s key is the public key The receiver key is the private key.

Hash Function Network Security: Cryptography One-way encryption Use no key Generate a digital fingerprint of a plaintext Used to encrypt passwords

Extensions Network Security: Cryptography Fuzzy hashes are an area of intense research and represent hash values that represent two inputs that are similar. Fuzzy hashes are used to detect documents, images, or other files that are close to each other with respect to content

Why Three ! Network Security: Cryptography Hash Function Integrity SKC Privacy & Confidentially PKC Non-repudiation User authentication

Conclusion

Conclusion Network Security: Conclusion Networks Information Internet Tools & Techniques Cryptography

Thank you for Listening