Network Security W10

What is the purpose of a network?

To allow the exchange of information between hosts using applications governed by protocols.

How is data transmitted in a network?

Through packets using various access media, links, packet switches, and protocols like HTTP, FTP, SMTP, TCP, and IP.

What is a network architecture?

A set of layers and protocols that define how data is transmitted over a network.

What is a protocol in networking?

A set of rules or agreements between layers that govern data communication.

What are the components of the layered network model?

Layers, services, interfaces, entities, and protocols.

What is a helpful mnemonic for the TCP/IP model?

"Armadillos Take In New Ants" → Application, Transport, Internet, Network Access.

Where is security implemented in the OSI model?

• Physical: Secure cables/fiber

• Data Link: Point-to-point encryption

• Network: IPsec, firewalls

• Transport: Encrypted connections

• Intermediate: Secure Socket Layer (SSL)

What is cryptography?

A security tool that uses encryption to limit message access to intended recipients.

What are the components of encryption?

A set of keys, messages, and ciphertext.

What is a major drawback of symmetric encryption?

The need to securely share the key, which compromises security if intercepted.

What is public key cryptography?

Encryption using a public key and decryption using a private key.

Why is public key encryption more secure than symmetric?

Only the receiver has the private key to decrypt the message.

What is a substitution cipher?

A cipher that replaces one letter with another.

What is a transposition cipher?

A cipher that rearranges the order of characters without changing them.

What is a product cipher?

A cipher combining multiple steps of substitution and transposition.

What is DES?

Data Encryption Standard; processes 64-bit blocks in 19 iterations using transpositions and combinations.

What is AES?

Advanced Encryption Standard; uses 128-bit encryption keys for stronger security.

What is cipher block chaining?

An encryption method where each encrypted block is fed into the next encryption step.

What is symmetric key cryptography?

Encryption and decryption using the same shared key.