Unit 4 Review

What is one use of public key encryption (or public key cryptography)?

• It prevents people from hacking into your computer or intercepting your on­line conversation.

• It allows data to be sent securely—decodable only by the intended recipient—as long as nobody is hacking the line or "listening in."

• It allows data to be sent securely—decodable only by the intended recipient—even along insecure lines.

• It prevents people from sending you unwanted emails or other spam.

• It is free for the public to use, unlike private systems that must be paid for.

How does public key encryption (public key cryptography) differ from symmetric encryption?

• Public key encryption shares all necessary encryption information with everyone: it is public. Symmetric encryption shares decryption information only between the sender and receiver.

• Symmetric and public key encryption both use mathematics to encode messages, but symmetric encryption uses numbers that have symmetry, like 137731 or 82328.

• They are not different. Symmetric and public key encryption both require each party to share all encryption/decryption information with the other.

• Public key encryption makes the encryption key public, and does not require the sender to know any private information about how to decrypt the message.

The terms "bandwidth" and "latency" are both used in talking about the amount of time it takes to transmit information. What is the difference between them?

• There is no difference; they are synonyms. Both describe the total TIME it takes to move one megabyte of information.

• There is no difference; they are synonyms. Both describe the total AMOUNT of information that can be moved in one second.

• Bandwidth is a measure of the rate at which the information moves through the system, the amount of data in a fixed time. Latency refers primarily to the wait time before the system can move the data.

• They are roughly opposites. Low bandwidth is caused by high latency.

People sometimes treat "the cloud" and "the Internet" as if they mean the same thing. They don't. Which of these explains the difference?

• The Internet is a network of computers. The cloud means all the servers on the Internet, thought of as one big server because you don't know exactly what computer has your data on it.

• The Internet is the path you follow to reach the cloud. The cloud refers to all of the computers on the Internet.

• The Internet is a cloud service provider. The cloud is the storage place for all data.

• The cloud is bigger than the Internet.

Choose the best way to complete this sentence: Redundancy improves reliability because...

• ...repeating instructions in a program helps in case an instruction is not executed properly.

• ...having multiple parallel systems capable of doing a task, and a way to monitor success, allows a backup system to be chosen if the originally chosen system fails.

• ...having more equipment on the job makes the job faster and cheaper.

• ...repeating a task several times assures that at least one of those times will work.

In computer science, a router is not something you stick down a blocked drainpipe. What is it?

• A computer router opens up a path for Internet communication, from beginning to end, carving it out just as a woodworking router hollows out a shape in wood.

• A router operates like an air traffic controller, making sure that two transmissions on the Internet are safely spaced and don't "crash" into each other.

• A router chooses an open route for the next step in the transmission of data sent over the Internet.

• A router is the device that encrypts your computer's data so that it can be sent over some Internet route.

Which of the following is an advantage of a lossless compression algorithm over a lossy compression algorithm?

• A lossless compression algorithm can guarantee that compressed information is kept secure, while a lossy compression algorithm cannot.

• A lossless compression algorithm can guarantee reconstruction of original data, while a lossy compression algorithm cannot.

• A lossless compression algorithm typically allows for faster transmission speeds than does a lossy compression algorithm.

• A lossless compression algorithm typically provides a greater reduction in the number of bits stored or transmitted than does a lossy compression algorithm.

Consider the following numeric values.

Binary 1011

Binary 1101

Decimal 5

Decimal 12

Which of the following lists the values in order from least to greatest?

• Decimal 5, binary 1011, decimal 12, binary 1101

• Decimal 5, decimal 12, binary 1011, binary 1101

• Decimal 5, binary 1011, binary 1101, decimal 12

• Binary 1011, binary 1101, decimal 5, decimal 12

Each user creates a profile with the following personal preferences.

Screen brightness and contrast

Choice of typeface and font size

Amount of spacing between lines of text

Activation of a text-to-speech feature that reads the text out loud

When the user launches the application, the application scans the user’s face and uses facial recognition software to determine the user’s identity. Once the user has been identified, the user’s personal preferences are applied to whatever book or article the user chooses to read.

The application stores all user information in a database, including personal preferences and a record of previously read books and articles.

From the perspective of the application’s developers, which of the following is most likely to be a benefit of storing all user data in a database?

• The developers can analyze the data to make improvements to the application based on user behavior.

• The developers can analyze the data to ensure that no patterns emerge in the data.

• The developers can reduce the amount of data storage required to support the application.

• The developers can reduce the need for data encryption.

Which of the following is LEAST likely to be a contributing factor to the digital divide?

• Some individuals and groups are economically disadvantaged and cannot afford computing devices or Internet connectivity.

• Some individuals and groups do not have the necessary experience or education to use computing devices or the Internet effectively.

• Some parents prefer to limit the amount of time their children spend using computing devices or the Internet.

• Some residents in remote regions of the world do not have access to the infrastructure necessary to support reliable Internet connectivity.