CISSP Sybex Official Study Guide Chapter 7 Review Questions

Question 1

Brian computes the digest of a single sentence of text using a SHA-2 hash function. He then changes a single character of the sentence and computes the hash value again. Which one of the following statements is true about the new hash value?

A. The new hash value will be one character different from the old hash value.
B. The new hash value will share at least 50% of the characters of the old hash value.
C. The new hash value will be unchanged.
D. The new hash value will be completely different from the old hash value.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 271). Wiley. Kindle Edition.

Answer 1

D. The new hash value will be completely different from the old hash value.

Explanation:
D. It is not possible to determine the degree of difference between two inputs by comparing their hash values. Changing even a single character in the input to a hash function will result in completely different output.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Question 2

Which cryptographic algorithm forms the basis of the El Gamal cryptosystem?

A. RSA
B. Diffie-Hellman
C. 3DES
D. IDEA

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 271). Wiley. Kindle Edition.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 271). Wiley. Kindle Edition.

Answer 2

B. Diffie-Hellman

Explanation:
The El Gamal cryptosystem extends the functionality of the Diffie-Hellman key

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Question 3

If Richard wants to send an encrypted message to Sue using a public key cryptosystem, which key does he use to encrypt the message?

A. Richard’s public key
B. Richard’s private key
C. Sue’s public key
D. Sue’s private key

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 271). Wiley. Kindle Edition.

Answer 3

C. Sue’s public key

Explanation:
Richard must encrypt the message using Sue’s public key so that Sue can decrypt it using her private key. If he encrypted the message with his own public key, the recipient would need to know Richard’s private key to decrypt the message. If he encrypted it with his own private key, any user could decrypt the message using Richard’s freely available public key. Richard could not encrypt the message using Sue’s private key because he does not have access to it. If he did, any user could decrypt it using Sue’s freely available public key.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Question 4

If a 2,048-bit plaintext message were encrypted with the El Gamal public key cryptosystem, how long would the resulting ciphertext message be?

A. 1,024 bits
B. 2,048 bits
C. 4,096 bits
D. 8,192 bits

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 271). Wiley. Kindle Edition.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 271). Wiley. Kindle Edition.

Answer 4

C. 4,096 bits

Explanation:
C. The major disadvantage of the El Gamal cryptosystem is that it doubles the length of any message it encrypts. Therefore, a 2,048-bit plain-text message would yield a 4,096-bit ciphertext message when El Gamal is used for the encryption process.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Chapple, Mike; Stewart, James Michael; Gib Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Question 5

Acme Widgets currently uses a 1,024-bit RSA encryption standard companywide. The company plans to convert from RSA to an elliptic curve cryptosystem. If it wants to maintain the same cryptographic strength, what ECC key length should it use?

ciphertext message when El Gamal is used for the encryption process.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

A.
B. 512 bits
C. 1,024 bits
D. 2,048 bits

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 271). Wiley. Kindle Edition.

Answer 5

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Explanation:

Question 6

John wants to produce a message digest of a 2,048-byte message he plans to send to Mary. If he uses the SHA-1 hashing algorithm, what size will the message digest for this particular message be?

A. 160 bits
B. 512 bits
C. 1,024 bits
D. 2,048 bits

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 272). Wiley. Kindle Edition.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 272). Wiley. Kindle Edition.

Answer 6

A. 160 bits

Explanation:
The SHA-1 hashing algorithm always produces a 160-bit message digest, regardless of the size of the input message. In fact, this fixed-length output is a requirement of any secure hashing algorithm.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Question 7

Which one of the following technologies is considered flawed and should no longer be used?

A. SHA-3
B. PGP
C. WEP
D. TLS

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 272). Wiley. Kindle Edition.

Answer 7

C. WEP

Explanation:
The WEP algorithm has documented flaws that make it trivial to break. It should never be used to protect wireless networks.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Question 8

What encryption technique does WPA use to protect wireless communications?

A/ TKIP
B. DES
C. 3DES
D. AES

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 272). Wiley. Kindle Edition.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 272). Wiley. Kindle Edition.

Answer 8

A/ TKIP

Explanation:
Wi-Fi Protected Access (WPA) uses the Temporal Key Integrity Protocol (TKIP) to protect wireless communications. WPA2 uses AES encryption.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Question 9

Richard received an encrypted message sent to him from Sue. Which key should he use to decrypt the message?

A. Richard’s public key
B. Richard’s private key
C. Sue’s public key
D. Sue’s private key

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 272). Wiley. Kindle Edition.

Answer 9

B. Richard’s private key

Explanation:
Sue would have encrypted the message using Richard’s public key. Therefore, Richard needs to use the complementary key in the key pair, his private key, to decrypt the message.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Question 10

Richard wants to digitally sign a message he’s sending to Sue so that Sue can be sure the message came from him without modification while in transit. Which key should he use to encrypt the message digest?

A. Richard’s public key
B. Richard’s private key
C. Sue’s public key
D. Sue’s private key

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 272). Wiley. Kindle Edition.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 272). Wiley. Kindle Edition.

Answer 10

B. Richard’s private key

Explanation:
Richard should encrypt the message digest with his own private key. When Sue receives the message, she will decrypt the digest with Richard’s public key and then compute the digest herself. If the two digests match, she can be assured that the message truly originated from Richard.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Question 11

Which one of the following algorithms is not supported by the Digital Signature Standard?

A. Digital Signature Algorithm
B. RSA
C. El Gamal DSA
D. Elliptic Curve DSA

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 272). Wiley. Kindle Edition.

Answer 11

C. El Gamal DSA

Explanation:
C. The Digital Signature Standard allows federal government use of the Digital Signature Algorithm, RSA, or the Elliptic Curve DSA in conjunction with the SHA-1 hashing function to produce secure digital signatures.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 960). Wiley. Kindle Edition.

Question 12

Which International Telecommunications Union (ITU) standard governs the creation and endorsement of digital certificates for secure electronic communication?

A. X.500
B. X.509
C. X.900
D. X.905

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 273). Wiley. Kindle Edition.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 273). Wiley. Kindle Edition.

Answer 12

B. X.509

Explanation:
X.509 governs digital certificates and the public-key infrastructure (PKI). It defines the appropriate content for a digital certificate and the processes used by certificate authorities to generate and revoke certificates.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 961). Wiley. Kindle Edition.

Question 13

What cryptosystem provides the encryption/decryption technology for the commercial version of Phil Zimmerman’s Pretty Good Privacy secure email system?

A. ROT13
B. IDEA
C. ECC
D. El Gamal

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 273). Wiley. Kindle Edition.

Answer 13

B. IDEA

Explanation:
Pretty Good Privacy uses a “web of trust” system of digital signature verification. The encryption technology is based on the IDEA private key cryptosystem.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 961). Wiley. Kindle Edition.

Question 14

What TCP/IP communications port is used by Transport Layer Security traffic?

A. 80
B. 220
C. 443
D. 559

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 273). Wiley. Kindle Edition.

Answer 14

C. 443

Explanation:
Transport Layer Security uses TCP port 443 for encrypted client-server communications.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 961). Wiley. Kindle Edition.

Question 15

What type of cryptographic attack rendered Double DES (2DES) no more effective than standard DES encryption?

A. Birthday attack
B. Chosen ciphertext attack
C. Meet-in-the-middle attack
D. Man-in-the-middle attack

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 273). Wiley. Kindle Edition.

Answer 15

C. Meet-in-the-middle attack

Explanation:
C. The meet-in-the-middle attack demonstrated that it took relatively the same amount of computation power to defeat 2DES as it does to defeat standard DES. This led to the adoption of Triple DES (3DES) as a standard for government communication.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 961). Wiley. Kindle Edition.

Question 16

Which of the following tools can be used to improve the effectiveness of a brute-force password cracking attack?

A. Rainbow tables
B. Hierarchical screening
C. TKIP
D. Random enhancement

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 273). Wiley. Kindle Edition.

Answer 16

A. Rainbow tables

Explanation:
Rainbow tables contain precomputed hash values for commonly used passwords and may be used to increase the efficiency of password cracking attacks.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 961). Wiley. Kindle Edition.

Question 17

Which of the following links would be protected by WPA encryption?

A. Firewall to firewall
B. Router to firewall
C. Client to wireless access point
D. Wireless access point to router

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 273). Wiley. Kindle Edition.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 273). Wiley. Kindle Edition.

Answer 17

C. Client to wireless access point

Explanation:
The Wi-Fi Protected Access protocol encrypts traffic passing between a mobile client and the wireless access point. It does not provide end-to-end encryption.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 961). Wiley. Kindle Edition.

Question 18

What is the major disadvantage of using certificate revocation lists?

A. Key management
B. Latency
C. Record keeping
D. Vulnerability to brute-force attacks

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 274). Wiley. Kindle Edition.

Answer 18

B. Latency

Explanation:
Certificate revocation lists (CRLs) introduce an inherent latency to the certificate expiration process due to the time lag between CRL distributions.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 961). Wiley. Kindle Edition.

Question 19

Which one of the following encryption algorithms is now considered insecure?

A. El Gamal
B. RSA
C. Elliptic Curve Cryptography
D. Merkle-Hellman Knapsack

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 274). Wiley. Kindle Edition.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 274). Wiley. Kindle Edition.

Answer 19

D. Merkle-Hellman Knapsack

Explanation:
The Merkle-Hellman Knapsack algorithm, which relies on the difficulty of factoring super-increasing sets, has been broken by cryptanalysts.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 961). Wiley. Kindle Edition.

Question 20

What does IPsec define?

A. All possible security classifications for a specific configuration
B. A framework for setting up a secure communication channel
C. The valid transition states in the Biba model D. TCSEC security categories

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 274). Wiley. Kindle Edition.

Answer 20

B. A framework for setting up a secure communication channel

Explanation:
IPsec is a security protocol that defines a framework for setting up a secure channel to exchange information between two entities.

Chapple, Mike; Stewart, James Michael; Gibson, Darril. (ISC)2 CISSP Certified Information Systems Security Professional Official Study Guide (p. 961). Wiley. Kindle Edition.