- (Topic 5)
What does the directive of the European Union on Electronic Signatures deal with?
Correct Answer:C
Reference: FORD, Warwick & BAUM, Michael S., Secure Electronic Commerce: Building the Infrastructure for Digital Signatures and Encryption (2nd Edition), 2000, Prentice Hall PTR, Page 589; Directive 1999/93/EC of 13 December 1999 on a Community framework for electronic signatures.
- (Topic 5)
Which of the following statements pertaining to stream ciphers is correct?
Correct Answer:B
A stream cipher is a type of symmetric encryption algorithm that operates on continuous streams of plain text and is appropriate for hardware-based encryption.
Stream ciphers can be designed to be exceptionally fast, much faster than any block cipher. A stream cipher generates what is called a keystream (a sequence of bits used as a key).
Stream ciphers can be viewed as approximating the action of a proven unbreakable cipher, the one-time pad (OTP), sometimes known as the Vernam cipher. A one-time pad uses a keystream of completely random digits. The keystream is combined with the plaintext digits one at a time to form the ciphertext. This system was proved to be secure by Claude Shannon in 1949. However, the keystream must be (at least) the same length as the plaintext, and generated completely at random. This makes the system very cumbersome to implement in practice, and as a result the one-time pad has not been widely used,
except for the most critical applications.
A stream cipher makes use of a much smaller and more convenient key ?? 128 bits, for example. Based on this key, it generates a pseudorandom keystream which can be combined with the plaintext digits in a similar fashion to the one-time pad. However, this comes at a cost: because the keystream is now pseudorandom, and not truly random, the proof of security associated with the one-time pad no longer holds: it is quite possible for a stream cipher to be completely insecure if it is not implemented properly as we have seen with the Wired Equivalent Privacy (WEP) protocol.
Encryption is accomplished by combining the keystream with the plaintext, usually with the bitwise XOR operation.
Source: DUPUIS, Clement, CISSP Open Study Guide on domain 5, cryptography, April 1999.
More details can be obtained on Stream Ciphers in RSA Security's FAQ on Stream Ciphers.
- (Topic 4)
A prolonged high voltage is a:
Correct Answer:C
A prolonged high voltage is a surge.
From: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, 3rd. Edition McGraw- Hill/Osborne, 2005, page 368.
- (Topic 2)
Which of the following describes a logical form of separation used by secure computing systems?
Correct Answer:B
Source: TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.
- (Topic 2)
Which of the following would MOST likely ensure that a system development project meets business objectives?
Correct Answer:B
Effective user involvement is the most critical factor in ensuring that the application meets business objectives.
A great way of getting early input from the user community is by using Prototyping. The prototyping method was formally introduced in the early 1980s to combat the perceived weaknesses of the waterfall model with regard to the speed of development. The objective is to build a simplified version (prototype) of the application, release it for review, and use the feedback from the users?? review to build a second, better version.
This is repeated until the users are satisfied with the product. t is a four-step process: initial concept,
design and implement initial prototype,
refine prototype until acceptable, and complete and release final version.
There is also the Modified Prototype Model (MPM. This is a form of prototyping that is ideal for Web application development. It allows for the basic functionality of a desired system or component to be formally deployed in a quick time frame. The maintenance phase is set to begin after the deployment. The goal is to have the process be flexible enough so the application is not based on the state of the organization at any given time. As the organization grows and the environment changes, the application evolves with it, rather than being frozen in time.
Reference(s) used for this question:
Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition ((ISC)2 Press) (Kindle Locations 12101-12108 and 12099-12101). Auerbach Publications. Kindle Edition.
and
Information Systems Audit and Control Association, Certified Information Systems Auditor 2002 review manual, chapter 6: Business Application System Development, Acquisition, Implementation and Maintenance (page 296).