Which of the following is less likely to be used today in creating a Virtual Private Network?
正解: D
Section: Network and Telecommunications Explanation/Reference: L2F (Layer 2 Forwarding) provides no authentication or encryption. It is a Protocol that supports the creation of secure virtual private dial-up networks over the Internet. At one point L2F was merged with PPTP to produce L2TP to be used on networks and not only on dial up links. IPSec is now considered the best VPN solution for IP environments. Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002, Chapter 8: Cryptography (page 507).
SSCP 試験問題 182
Which of the following is most affected by denial-of-service (DOS) attacks?
正解: D
Explanation/Reference: Denial of service attacks obviously affect availability of targeted systems. Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 3: Telecommunications and Network Security (page 61).
SSCP 試験問題 183
Which of the following was designed as a more fault-tolerant topology than Ethernet, and very resilient when properly implemented?
正解: C
Explanation/Reference: Token Ring was designed to be a more fault-tolerant topology than Ethernet, and can be a very resilient topology when properly implemented. Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 72.
SSCP 試験問題 184
___________ programs decrease the number of security incidents, educate users about procedures, and can potentially reduce losses.
正解: B
SSCP 試験問題 185
Brute force attacks against encryption keys have increased in potency because of increased computing power. Which of the following is often considered a good protection against the brute force cryptography attack?
正解: B
If we assume a crytpo-system with a large key (and therefore a large key space) a brute force attack will likely take a good deal of time - anywhere from several hours to several years depending on a number of variables. If you use a session key for each message you encrypt, then the brute force attack provides the attacker with only the key for that one message. So, if you are encrypting 10 messages a day, each with a different session key, but it takes me a month to break each session key then I am fighting a loosing battle. The other answers are not correct because: "The use of good key generators" is not correct because a brute force key attack will eventually run through all possible combinations of key. Therefore, any key will eventually be broken in this manner given enough time. "Nothing can defend you against a brute force crypto key attack" is incorrect, and not the best answer listed. While it is technically true that any key will eventually be broken by a brute force attack, the question remains "how long will it take?". In other words, if you encrypt something today but I can't read it for 10,000 years, will you still care? If the key is changed every session does it matter if it can be broken after the session has ended? Of the answers listed here, session keys are "often considered a good protection against the brute force cryptography attack" as the question asks. "Algorithms that are immune to brute force key attacks" is incorrect because there currently are no such algorithms. References: Official ISC2 Guide page: 259 All in One Third Edition page: 623
