In which of the following phases of system development life cycle (SDLC) is contingency planning most important?
Correct Answer: A
Contingency planning requirements should be considered at every phase of SDLC, but most importantly when a new IT system is being conceived. In the initiation phase, system requirements are identified and matched to their related operational processes, allowing determination of the system's appropriate recovery priority. Source: SWANSON, Marianne, & al., National Institute of Standards and Technology (NIST), NIST Special Publication 800-34, Contingency Planning Guide for Information Technology Systems, December 2001 (page 12). and The Official ISC2 Guide to the CBK, Second Edition, Application Security, page 180-185
Question 647
Which type of encryption is considered to be unbreakable if the stream is truly random and is as large as the plaintext and never reused in whole or part?
Correct Answer: A
Explanation/Reference: OTP or One Time Pad is considered unbreakable if the key is truly random and is as large as the plaintext and never reused in whole or part AND kept secret. In cryptography, a one-time pad is a system in which a key generated randomly is used only once to encrypt a message that is then decrypted by the receiver using the matching one-time pad and key. Messages encrypted with keys based on randomness have the advantage that there is theoretically no way to "break the code" by analyzing a succession of messages. Each encryption is unique and bears no relation to the next encryption so that some pattern can be detected. With a one-time pad, however, the decrypting party must have access to the same key used to encrypt the message and this raises the problem of how to get the key to the decrypting party safely or how to keep both keys secure. One-time pads have sometimes been used when the both parties started out at the same physical location and then separated, each with knowledge of the keys in the one-time pad. The key used in a one-time pad is called a secret key because if it is revealed, the messages encrypted with it can easily be deciphered. One-time pads figured prominently in secret message transmission and espionage before and during World War II and in the Cold War era. On the Internet, the difficulty of securely controlling secret keys led to the invention of public key cryptography. The biggest challenge with OTP was to get the pad security to the person or entity you wanted to communicate with. It had to be done in person or using a trusted courrier or custodian. It certainly did not scale up very well and it would not be usable for large quantity of data that needs to be encrypted as we often time have today. The following answers are incorrect: - One time Cryptopad: Almost but this isn't correct. Cryptopad isn't a valid term in cryptography. - Cryptanalysis: Sorry, incorrect. Cryptanalysis is the process of analyzing information in an effort to breach the cryptographic security systems. - PGP - Pretty Good Privacy: PGP, written by Phil Zimmermann is a data encryption and decryption program that provides cryptographic privacy and authentication for data. Still isn't the right answer though. Read more here about PGP. The following reference(s) was used to create this question: To get more info on this Qs or any Qs of Security+, subscribe to the CCCure Holistic Security+ CBT available at: http://www.cccure.tv and http://users.telenet.be/d.rijmenants/en/otp.htm and http://en.wikipedia.org/wiki/One-time_pad and http://searchsecurity.techtarget.com/definition/one-time-pad
Question 648
What is defined as the rules for communicating between computers on a Local Area Network (LAN)?
Correct Answer: A
Section: Network and Telecommunications Explanation/Reference: Media contention occurs when two or more network devices have data to send at the same time. Because multiple devices cannot talk on the network simultaneously, some type of method must be used to allow one device access to the network media at a time. This is done in two main ways: carrier sense multiple access collision detect (CSMA/CD) and token passing. In networks using CSMA/CD technology such as Ethernet, network devices contend for the network media. When a device has data to send, it first listens to see if any other device is currently using the network. If not, it starts sending its data. After finishing its transmission, it listens again to see if a collision occurred. A collision occurs when two devices send data simultaneously. When a collision happens, each device waits a random length of time before resending its data. In most cases, a collision will not occur again between the two devices. Because of this type of network contention, the busier a network becomes, the more collisions occur. This is why performance of Ethernet degrades rapidly as the number of devices on a single network increases. In token-passing networks such as Token Ring and FDDI, a special network frame called a token is passed around the network from device to device. When a device has data to send, it must wait until it has the token and then sends its data. When the data transmission is complete, the token is released so that other devices may use the network media. The main advantage of token-passing networks is that they are deterministic. In other words, it is easy to calculate the maximum time that will pass before a device has the opportunity to send data. This explains the popularity of token-passing networks in some real-time environments such as factories, where machinery must be capable of communicating at a determinable interval. For CSMA/CD networks, switches segment the network into multiple collision domains. This reduces the number of devices per network segment that must contend for the media. By creating smaller collision domains, the performance of a network can be increased significantly without requiring addressing changes. The following are incorrect answers: LAN topologies: Think of a topology as a network's virtual shape or structure. This shape does not necessarily correspond to the actual physical layout of the devices on the network. For example, the computers on a home LAN may be arranged in a circle in a family room, but it would be highly unlikely to find a ring topology there. Common topologies are: bus, ring, star or meshed. See THIS LINK for more information. LAN transmission methods: refer to the way packets are sent on the network and are either unicast, multicast or broadcast. See THIS LINK for more information. Contention Access Control: This is a bogus detractor. Contention is a real term but Contention Access Control is just made up. Contention methods is very closely related to Media Access Control methods. In communication networks, contention is a media access method that is used to share a broadcast medium. In contention, any computer in the network can transmit data at any time (first come-first served). This system breaks down when two computers attempt to transmit at the same time. This is a case of collision. To avoid collision, carrier sensing mechanism is used. Here each computer listens to the network before attempting to transmit. If the network is busy, it waits until network quiets down. In carrier detection, computers continue to listen to the network as they transmit. If computer detects another signal that interferes with the signal it is sending, it stops transmitting. Both computers then wait for random amount of time and attempt to transmit. Contention methods are most popular media access control method on LANs. Reference(s) used for this question: http://docwiki.cisco.com/wiki/Introduction_to_LAN_Protocols#LAN_Media-Access_Methods http://en.wikipedia.org/wiki/Contention_%28telecommunications%29
Question 649
Which of the following is BEST defined as a physical control?
Correct Answer: B
Section: Security Operation Adimnistration Explanation/Reference: Physical controls are items put into place to protect facility, personnel, and resources. Examples of physical controls are security guards, locks, fencing, and lighting. The following answers are incorrect answers: Monitoring of system activity is considered to be administrative control. Identification and authentication methods are considered to be a technical control. Logical access control mechanisms is also considered to be a technical control. Reference(s) used for this question: Harris, Shon (2012-10-25). CISSP All-in-One Exam Guide, 6th Edition (Kindle Locations 1280-1282). McGraw- Hill. Kindle Edition.
Question 650
What is called the verification that the user's claimed identity is valid and is usually implemented through a user password at log-on time?
Correct Answer: A
Section: Access Control Explanation/Reference: Authentication is verification that the user's claimed identity is valid and is usually implemented through a user password at log-on time. Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 36.
