OSI Ch. 6&7
D. RSA
6-11: Which of the following is an encryption method developed by three mathematicians in the 1970s?
C. DES
6-12: Which encryption algorithm uses a variable-length symmetric key?
C. AES
6-13: Which of the following encryption algorithms uses three key ciphers in a block system, and uses the Rijndael algorithm?
B. Speed of the algorithm
6-14: If you are using a block cipher to encrypt large amounts of data, which of the following would be the most important consideration when deciding which cipher to use?
D. IDEA
6-15: Which of the following uses a total of 52 16-bit sub-keys?
C. Testing the encryption of your own network
6-16: Which of the following is the most common legitimate use for a password cracker?
A. A piece of encrypted data added to other data to verify the sender
6-17: What is a digital signature?
C. To validate the sender of a digital signature or software
6-18: What is the purpose of a certificate?
C. A private certificate authority
6-19: Who issues certificates?
A. No matter how secure your network is, the data being transmitted is still vulnerable without encryption
6-1: Why is encryption an important part of security?
A. It does not disrupt letter frequency
6-3: Which of the following is the primary weakness in the Caesar cipher?
B. Multi-alphabet substitution
6-4: An improvement on the Caesar cipher that uses more than one shift is called a what?
A. AH
7-16: What protects the actual packet data in IPSec?
A. Key exchange
7-17: What is the purpose of IKE?
B. Point-to-point tunneling protocol
7-1: PPTP is an acronym for which of the following?
B. Playback attacks
7-10: What is the primary vulnerability in SPAP?
A. MPPE
7-11: What encryption does PPTP use?
C. Used only with IP networks
7-12: Which of the following is a weakness in PPTP?
A. AH, IKE, ESP, IPComp
7-13: What protocols make up IPSec?
D. Only transport mode does not encrypt the header
7-14: What is the difference between transport mode and tunnel mode in IPSec?
C. AH is not susceptible to replay attacks
7-15: What advantage does AH have over SPAP?
B. Layer 2 tunneling protocol
7-2: What does L2TP stand for?
D. PPP
7-3: PPTP is based on what earlier protocol?
C. Data link
7-4: At what layer of the OSI does PPTP operate?
C. Only voluntary tunneling allows standard PPP/non-VPN connection
7-5: What is the difference between voluntary and compulsory tunneling in PPTP?
B. EAP, CHAP
7-6: Which authentication protocols are available under PPTP?
A. It periodically re-authenticates
7-7: Which of the following is an important security feature in CHAP?
A. MS-CHAP, PAP, SPAP
7-8: Which authentication protocols are available with L2TP that are not available with PPTP?
A. PAP
7-9: Which of the following is generally considered to be the least secure?
B. Public key
6-10: What type of encryption uses a different key to encrypt the message than it uses to decrypt the message?
C. Caesar cipher
6-2: Which of the following is the oldest known encryption method?
C. XOR
6-5: Which binary mathematical operation can be used for a simple encryption method?
A. It does not change letter or word frequency
6-6: Why is the method described in Question 5 not secure?
B. DES
6-7: Which of the following is a symmetric key system using blocks?
D. It is complex
6-8: What is the primary advantage of the encryption algorithm described in Question 7?
C. 56 bit
6-9: What size key does this system use?
