Network Security

Answer the below questions. The answer to each question should be more than  150 words.

NO plagiarism.

Question: What is the OSI security architecture?

Question: What is the difference between passive and active security threats?

Question: List and briefly define categories of passive and active security attacks.

Question: List and briefly define categories of security services.

Question: List and briefly define categories of security mechanisms.

Question: List and briefly define the fundamental security design principles.

Question: Explain the difference between an attack surface and an attack tree.

Question: What are the essential ingredients of a symmetric cipher?

Question: What are the two basic functions used in encryption algorithms?

Question: How many keys are required for two people to communicate via a symmetric cipher?

Question: What is the difference between a block cipher and a stream cipher?

Question: What are the two general approaches to attacking a cipher?

Question: Why do some block cipher modes of operation only use encryption while others use both encryption and decryption?

Question: What is triple encryption?

Question: Why is the middle portion of 3DES a decryption rather than an encryption?