Tuesday, May 13, 2014

CISA Exam Preparation (Question 91 ~ 95)

(91) Which of the following aspects of symmetric key encryption influenced the development of asymmetric encryption?
A. Processing power
B. Volume of data
C. Key distribution
D. Complexity of the algorithm

Explanation:
Symmetric key encryption requires that the keys be distributed. The larger the user group, the more challenging the key distribution. Symmetric key cryptosystems are generally less complicated and, therefore, use less processing power than asymmetrictechniques , thus making it ideal for encrypting a large volume of datA . The major disadvantage is the need to get the keys into the hands of those with whom you want to exchange data, particularly in e-commerce environments, where customers are unknown, untrusted entities.
(92) Which of the following is the MOST important criterion when selecting a location for an offsite storage facility for IS backup files? The offsite facility must be:
A. physically separated from the data center and not subject to the same risks.
B. given the same level of protection as that of the computer data center.
C. outsourced to a reliable third party.
D. equipped with surveillance capabilities.

Explanation:
It is important that there be an offsite storage location for IS files and that it be in a location not subject to the same risks as the primary data center. The other choices are all issues that must be considered when establishing the offsite location, but they are not as critical as the location selection.
(93) If a database is restored using before-image dumps, where should the process begin following an interruption?
A. Before the last transaction
B. After the last transaction
C. As the first transaction after the latest checkpoint
D. As the last transaction before the latest checkpoint

Explanation:
If before images are used, the last transaction in the dump will not have updated the database prior to the dump being taken. The last transaction will not have updated the database and must be reprocessed. Program checkpoints are irrelevant in this situation.
(94) In addition to the backup considerations for all systems, which of the following is an important consideration in providing backup for online systems?
A. Maintaining system software parameters
B. Ensuring periodic dumps of transaction logs
C. Ensuring grandfather-father-son file backups
D. Maintaining important data at an offsite location

Explanation:
Ensuring periodic dumps of transaction logs is the only safe way of preserving timely historical datA . The volume of activity usually associated with an online system makes other more traditional methods of backup impractical.
(95) As updates to an online order entry system are processed, the updates are recorded on a transaction tape and a hard copy transaction log. At the end of the day, the order entry files are backed up on tape. During the backup procedure, a drive malfunctions and the order entry files are lost. Which of the following is necessary to restore these files?
A. The previous day’s backup file and the current transaction tape
B. The previous day’s transaction file and the current transaction tape
C. The current transaction tape and the current hard copy transaction log
D. The current hard copy transaction log and the previous day’s transaction file


Explanation:
The previous day’s backup file will be the most current historical backup of activity in the system. The current day’s transaction file will contain all of the day’s activity. Therefore, the combination of these two files will enable full recovery upto the point of interruption.

- Muhammad Idham Azhari

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