Overview of ESP in Network Security Answers 1. Which layer of the TCP/IP model does ESP operate at? A. Transport Layer B. Application Layer C. Network Layer D. Physical Layer Answer: Network Layer (C) ESP operates at the Network Layer (Layer 3), ensuring secure IP communication. 2. What does the ESP Sequence Number primarily help with? A. Determining the encryption algorithm used B. Detecting duplicate packets C. Calculating the hash value for integrity D. Verifying the sender's identity Answer: Detecting duplicate packets (B) The ESP Sequence Number is used to detect duplicate packets and ensure ordered delivery. 3. In which mode does ESP encrypt only the payload of the IP packet? A. Tunnel Mode B. Payload Encryption Mode C. Full Encryption Mode D. Transport Mode Answer: Transport Mode (D) In Transport Mode, ESP encrypts only the payload, as opposed to Tunnel Mode which encrypts the entire packet. 4. Which of the following is NOT a fundamental function of ESP? A. Confidentiality B. Encryption of the entire packet C. Authentication D. Integrity Answer: Encryption of the entire packet (B) While ESP does provide encryption, the specific function of encrypting the entire packet relates to Tunnel Mode rather than being a core function. 5. What role does the Security Parameter Index (SPI) play in ESP? A. It serves as a unique identifier for the security association. B. It holds the digital signatures for authentication. C. It identifies the encryption algorithm used. D. It calculates the integrity check value. Answer: It serves as a unique identifier for the security association. (A) SPI acts as a unique identifier for the specific security association (SA) involved in the packet. 6. Which of the following cryptographic algorithms is commonly used with ESP? A. SHA-512 B. AES C. RC4 D. Twofish Answer: AES (B) AES is one of the commonly used cryptographic algorithms for encryption within ESP. 7. What is the primary benefit of using ESP in data transmission? A. Increased bandwidth B. Faster transmission speeds C. Reduction of network congestion D. Data confidentiality Answer: Data confidentiality (D) The primary benefit of ESP is protecting data confidentiality during its transmission. 8. What does the ESP Trailer contain? A. The unique SPI and next header B. The payload data and encryption key C. The sequence number and ICV D. Authentication field and padding Answer: Authentication field and padding (D) The ESP Trailer contains the authentication field alongside the associated padding.