CS 101 Exam 2
Zombies
A botmaster uses malware to hijack hundreds to many thousands of computers and is able to remotely control them all, including the ability to update the malware and to introduce other programs such as spyware. Hijacked computers are called zombies
Ransomware
A botnet may be used to install ransomware, which holds the data on a computer or the use of the computer hostage until a payment is made. Ransomware encrypts the target's files, and the attacker tells the victim to make a payment of a specified amount to a special account to receive the decryption key
4G
"fourth generation"; faster than 3G; built specifically for Internet traffic but not standard yet • Both 3G and 4G used mostly in smartphones
3G
"third generation"; uses existing cellphone system; handles voice, email, multimedia
VPNs
(virtual private networks): use a public network (usually the Internet) plus intranets and extranets to connect an organization's various sites) but on a private basis, via encryption and authentication; regular Internet users do not have access to the VPN's data and information. Use firewalls for security.
What You Need to Connect
1. An access device (computer with modem) 2. A means of connection (phone line, cable hookup, or wireless) 3. An Internet service provider (ISP)
Web 3.0: Computer-Generated Information
• information will be computer-generated with less human interaction required to discover and integrate that information. • Two ideas might form the basis for Web 3.0 — semantic markup and a personal browser. -Semantic markup: Data interchange formats that will allow machines to understand the meaning — or "semantics"— of information on the web. -The Web 3.0 browser will probably act as a personal assistant because every user will have a unique Internet profile based on his or her browsing history. The more you use the Web, the more your browser learns about you and the less specific you'll need to be with your questions.
Web 2.0: The Social Web
• refers to the web viewed as a medium in which interactive experience, in the form of blogs, wikis, forums, social networking, and so on, plays a more important role than simply accessing information. • The move toward a more social, collaborative, interactive, and responsive web; has led to the "social web," giving rise to: -Social networking sites: Online communities that allow members to keep track of friends and share photos, videos, music, stories, and ideas (e.g., Facebook, LinkedIn). -Media-sharing sites: Online social networks in which members share media such as photos, videos, music, ideas (e.g., YouTube, Flicker, Shutterfly). -Social-network aggregators: Collect content from all of a user's various social network profiles into one place, then allow him or her to track friends and share other social network activities (e.g., Mugshot, Readr).
Tablets
A general-purpose computer contained in a single panel; it is a combination of smartphone and laptop computer with wireless connections, a 7- to 12-inch multi-touch screen, and a virtual screen
Wireless Internet Service Provider (WISP)
AT&T, T-Mobile, Verizon Wireless, Sprint, Credo • Enables wireless-equipped laptop/tablet and smartphone users to access Internet
Network Architecture - Peer-to-Peer (P2P)
All computers on the network are "equal" and communicate directly with one another, without relying on servers.
Network Components
All networks have several things in common: • wired = twisted-pair, coaxial cable, fiber-optic cable • wireless = infrared, microwave, radio, Wi-Fi, satellite • Hosts and Nodes: Client/server network has a host computer, which controls the network; a node is any device attached to the network. • Packets: fixed-length blocks of data for transmission, reassembled after transmission. • Protocols: set of conventions, or rules, governing the exchange of data between hardware and/or software components in the network; built into the hardware or software you are using. • The protocol in your communications software specifies how receiver devices will acknowledge sending devices, a matter called handshaking. Handshaking establishes the fact that the circuit is available and operational. It also establishes the level of device compatibility and the speed of transmission. • In addition, protocols specify the type of electronic connections used, the timing of message exchanges, and error-detection techniques. • Each packet, or electronic message, carries four types of information that will help it get to its destination; 1. the sender's address (IP) 2. the intended receiver's address 3. how many packets the complete message has been broken into 4. the number of this particular packet. The packets carry the data in the protocols that the Internet uses—that is, TCP/IP
Wireless: What you Already Know
Bandwidth: range (band) of frequencies that a transmission medium can carry in a given period of time • Analog bandwidth is expressed in hertz, digital bandwidth usually in bits per second (bps) • Narrowband(voiceband): used for regular telephone communications -Transmission rate 1.5 megabits per second or less • Broadband: For high-speed data and high-quality audio and video; wide band of frequencies -Transmission rate 1.5 megabits per second to 1 gigabit per second or more • TCP/IP (Ch. 2) is the protocol for getting wired devices connected to the Internet • WAP (wireless application protocol): Wireless handheld devices such as cellphones use the Wireless Application Protocol for connecting wireless users to the Web. Just as the protocol TCP/IP was designed to provide a wired connection to your Internet access provider, WAP is a standard designed to link nearly all mobile devices telecommunications carriers' wireless networks and content providers.
High speed
Cable modem • TV cable system with Internet connection; company usually supplies cable modem • Is always on • Receives data at up to 100 Mbps; sends at about 2-8 Mbps
Metropolitan area network (MAN)
Communications network covering a city or a suburb. Many cellphone systems are MANs.
Wide area network (WAN)
Communications network that covers a wide geographic area, such as a country or the world. Most long-distance and regional telephone companies are WANs. WANs are used to connect local area networks. The best example of a WAN is the Internet.
Local Area Network (LAN)
Connects computers and devices in a limited geographic area, such as one office, one building, or a group of buildings close together. LANs are the basis for most office networks, and the organization that runs the LAN owns it. WANs and MANs generally use a common carrier—a telecommunications company that hires itself out to the public to provide communications transmission services—for at least part of its connections. • A home area network is a LAN
Network Architecture - Client/Server
Consists of clients, which are computers that request data, and servers, which are computers that supply data. • File servers act like a network-based shared disk drive. • Database servers store data but don't store programs. • Print servers connect one or more printers and schedule and control print jobs. • Mail servers manage email.
3 major trends in Information Technology
Convergence, Portability, Personalization
Emails, netiquette
Don't waste people's time, Don't write anything that you would not say to a person's face, Include helpful subject and signature lines, Be clear and concise, Avoid spelling and grammatical errors, Avoid SHOUTING and flaming, Be careful with jokes, Avoid sloppiness, but avoid criticizing other's sloppiness, Don't send huge file attachments unless requested, When replying, quote only the relevant portion, Don't over-forward
Wired Connections for your home
Ethernet - standard for linking all devices in a LAN • Connect to PC's Ethernet network interface card (NIC) • For several PCs, get a switch to connect them all • 10 or 100 megabits per second HomePNA • Uses existing telephone wiring and jacks • Requires HomePNA NIC in your PC • Speeds of about 320 megabits per second Homeplug • Uses existing home electrical lines • Speeds of 200 megabits per second
Bandwidth
Expresses how much data can be sent through a communications channel in a given amount of time.
Long distance: one-way
GPS (Global Positioning System) • 24 to 32 MEO satellites continuously transmitting timed radio signals to identify Earth locations • Each satellite circles earth twice each day at 11,000 miles up • GPS receivers pick up transmissions from up to 4 satellites and pinpoint the receiver's location • Accurate within 3 - 50 feet, with a norm of 10 feet accuracy • Not all services based on GPS technology are reliable One-way Pagers: radio receivers that receive data sent from a special radio transmitter
Broadband
High-speed connections
Connecting - Bandwidth
However you connect to the Internet, this will determine the speed of your connection.
Pharming
Implanting malicious software on a victim's computer that redirects the user to an impostor web page even when the individual types the correct address into his or her browser. Use websites with URLs that begin with "https://" Some spyware removal programs can correct the corruption.
Short range for your home
Insteon • Combines electronic power line and wireless technology • Can send data at 13.1 kilobits per second with 150 ft. range ZigBee • Entirely wireless sensor technology • Can send data at 128 kilobits per second with 250 ft. range Z-Wave • Entirely wireless power-efficient technology • Can send data at 127 kilobits per second to range of 100 ft.
Digital Televisions
Interactive TV • Lets you interact with the show you're watching Internet TV • Television distributed via the Internet, viewable on computers and mobile devices Internet-Ready TV • TVs with broadband modems allow viewers to watch TV shows as well as go online to browse, get news, stream movies, view photos, etc.
Short range: two-way
Local Area Networks • Range 100 - 228 feet • Include Wi-Fi (802.11) type networks • Wi-Fi n is the latest and fastest Wi-Fi technology Personal Area Networks • Range 30 - 33 feet • Use Bluetooth, ultra wideband, and wireless USB Home Automation networks • Range 100 - 150 feet • Use Insteon, ZigBee, and Z-Wave standards
Internet Service Provider (ISP)
Local, regional, or national organization that provides access to the Internet for a fee — Comcast, Charter, AT&T.
Portable Media Players (PMPs)
Portable media players include music players, media players, and some mobile phones. • MP3 is a format that allows audio files to be compressed so they are small enough to be sent over the Internet and stored as digital files.
Personalization
Pros • customized just for them • personalized library of music • "favorites" or "bookmarks" • Access or contribute to blogs or personalized online diaries • PC software for personal projects • Get preselected news topics delivered to one's electronic devices as needed. Cons • Having many personalized devices leads to multitasking, which can lead to "absent presence" and non-focus
Portability
Pros • Devices that enable phone, texting, and email access from anywhere, portable digital music, GPS, and convenient cheap digital photos that allow people to remain connected even while on the move Cons • Bombardment by texts and phone calls; intrusiveness; time wasters • Lack of face-to-face contact can lead to misinterpretations
HTTP
Protocol Used to Access World Wide Web
Phishing
Sending forged email directing recipient to fake website. Purpose: to entice people to share personal or financial data. Fake website looks like real website, such as a bank's
Baseband
Slow type of connection that allows only one signal to be transmitted at a time.
Digital Cameras
Take video and photographs and digitally converts the analog data by recording images via an electronic image sensor (they do not require film). Point-and-shoot, Single-lens reflex (SLR)
History
The Internet began in 1969 as ARPANET. (U.S. Department of Defense) The Internet was text-only. In the early 1990s, multimedia became available on the Internet, and the World Wide Web (Web) was born
Digital Convergence
The combining of several industries - computers, communications, consumer electronics, entertainment, and mass media - through various devices that exchange data in digital form Pros: • Increased convenience of devices; more affordable; more functions Cons: • Multiple features that compromise the primary feature, no single feature works optimally • Security risks are increasing
Topology
The layout (shape) of a network • Star - all nodes are connected through a central network switch • Ring - all nodes are connected in a continuous loop • Bus - all nodes are connected to a single wire or cable • Tree - a bus network of star networks • Mesh - messages sent to the destination can take any possible shortest, easiest route to reach its destination. There must be at least two paths to any individual computer to create a mesh network. (Wireless networks are often implemented as a mesh, and the Internet is a mesh.)
Communication media (medium)
The means of interchanging or transmitting and receiving information. Twisted-Pair Wire (dial-up connections) -2 strands of insulated copper wire twisted around each other -Twisting reduces interference (crosstalk) from electrical signals • Data rates are 1 - 128 megabits per second (slow) Coaxial Cable -Insulated copper wire wrapped in a metal shield and then in an external plastic cover -Used for cable TV and cable Internet electric signals -Carries voice and data up to 200 megabits per second Fiber-optic cable -Dozens or hundreds of thin strands of glass or plastic that transmit pulses of light, not electricity -Can transmit up to 2 gigabits per second (very fast) -Have lower error rate than twisted-pair or coax -More expensive than twisted-pair or coax -Lighter and more durable than twisted-pair or coax -More difficult to tap into than twisted-pair or coax
The Web
The web and the Internet are not the same; the web is multimedia-based, and the Internet is not. The Internet is the infrastructure that supports the web.
Spoofing
Using fake email sender names so the message appears to be from a different source, so you will trust it. If you don't know the sender, don't open it
Types of Malware
Viruses, worms, Trojan horses, rootkits, blended threats
Smartphones
cellphone with microprocessor, memory, display screen, modem, apps, and Internet access
Client
computer requesting data or services
How cyber threats spread; what you can do about it
e-mail attachments, open Wi-Fi, clicking on sketchy websites, sharing infected disks anti-virus software, firewall
Instant Messaging
enables you to communicate by email with specified other users ("buddies") in real time. • Any user on a given email system can send a message and have it pop up instantly on the screen of anyone logged into that system. • To get IM: Download IM software from a supplier • Examples: AOL/AIM, Google Chat, Windows Messenger, Yahoo! Messenger • Done on computers; is not the same as texting.
Server
or host computer: central computer supplying data or services requested of it
Extranets
similar to intranets but allows use by selected outside entities, such as suppliers. Use firewalls for security
Spyware
software surreptitiously installed on your computer via the web. Hides on your PC/device and captures information about what is on the it, such as keystrokes and passwords. Types: Adware, Browser hijackers, search hijackers, key loggers
Browser
software that gets you to websites and their individual web pages and displays the content in such a way that the content appears mostly the same regardless of the computer, operating system, and display monitor. EX: safari, chrome, bing
Network
system of interconnected computers, telephones, and/or other communications devices that can communicate with one another and share applications and data.
Upload
transmit data from local to remote computer
Download
transmit data from remote to local computer
Intranets
use infrastructure and standards of the Internet and the web, but for an organization's internal use only. Use firewalls for security
Long distance: two-way
• 1G: First-Generation Cellular Service • Analog cellphones • Designed for voice communication using a system of hexagonal ground-area cells around transmitter-receiver cell towers • Good for voice - less effective for data because of handing off • 2G: Second-Generation Cellular Service • Uses digital signals • First digital voice cellular network • 3G: Third-Generation Cellular Service • Broadband technology • Carries data at high speeds: 144 kilobits per second up to 3.1 megabits per second • Accepts e-mail with attachments • Displays color video and still pictures • Plays music • 4G: Fourth-Generation Cellular Service: A nationwide 4G network is in development; up to 100 megabits/second. Enables faster Internet surfing • LTE (Long Term Evolution): an international standard widely adopted in the United States and several countries in Europe and Asia. LTE supports data transfer rates of up to 100 megabits per second over cellular networks.
Multimedia
• Allows you to get images, sound, video, and animation • May require a plug-in, player, or viewer -A downloadable program that adds a specific feature to a browser so it can view certain files -Examples: Flash, RealPlayer, QuickTime • Multimedia Applets -Small programs that can be quickly downloaded and run by most browsers -Java is the most common Applet language • Text & Images: great variety available -Example: Google Earth • Animation -The rapid sequencing of still images to create the appearance of motion -Used in video games and web images that seem to move, such as banners • Video & Audio -Downloaded completely before the file can be played, or -Downloaded as streaming video/audio -Examples: RealVideo and RealAudi
Analog
• But most phenomena in life are analog. • Analog signals use wave variations, continuously changing. • Sound, light, and temperature are analog forms. • Traditional TV and radio use analog signals. • Humans' vision operates in analog mode But analog data can be converted into digital form. Even though digital data is not as exact as analog data, it is easier to manipulate.
Telephone Modem
• Can be either internal or external • Maximum speed of 56 Kbps • Most ISPs offer local access number
Digital
• Computers use digital signals—0s and 1s, off and on. • All the data that a computer processes is a series of 0s and 1s. • Each signal is a bit.
DOS (Denial of Service Attack)
• Consists of making repeated requests of a computer or network device, thereby overloading it and denying access to legitimate users. • Used to target particular companies or individuals
Wireless Communication Basics
• Electromagnetic spectrum- of radiation is the basis of all telecommunications signals, wired and wireless. • Radio-frequency (RF) spectrum- is the part of the electromagnetic spectrum that carries most communications signals.
Snooping & Spam
• Email is not private -Corporate management has the right to view employees' email. -Friends can send email anywhere. -Not all ISPs protect their customers' privacy. -Deleted emails can be retrieved from a hard disk. • Electronic Junk Mail -Unsolicited email that takes up your time. -Delete it without opening the message. -Never reply to a spam message. -Do not click on "unsubscribe" at the bottom of an email. -When you sign up for something, don't give your email address. -Use spam filters. -Fight back by reporting new spammers to www.abuse.net or www.spamhaus.org.
Modems
• For data transmission over telephone lines and cables, modems are needed to convert analog data into digital data that computers can use. • Modem is short for modulate/demodulate. Modems modulate (convert) a computer's digital data to analog data, transmit it, then demodulate (reconvert) it back to digital data for the receiving computer. • Modems can convert data by modulating either a analog wave's amplitude or its frequency.
Cookies
• Little text files left on your hard disk by some websites you visit. • Can include your log-in name, password, browser preferences, and credit card information. • Every time you load a particular website, the browser sends the cookie back to the server to notify the website of your previous activity. • Can make visiting these websites next time more convenient and faster. • But cookies can be used to gather information about you and your browsing habits and history; this information can be used without your consent. • A first-party cookie is a cookie from a website that you have visited. Thirdparty cookies are placed by trusted partners of the websites you visit. (Third-party cookies are frequently placed by ad networks.)
Discussion Groups
• Mailing Lists: -One-way (to make announcements) or two-way (for discussions) email subscription lists -Email discussion groups on special-interest topics, in which all subscribers receive email messages sent to the group's email address • Newsgroups: -Giant electronic bulletin board for written discussions about specific subjects -To participate you need a newsreader program • Message Boards: -Special-interest discussion groups without newsreaders -Accessed through a web browser -A collection of messages on a particular topic is called a thread
Search Services & Search Engines
• Organizations that maintain databases accessible through websites to help you find information on the internet -Examples: portals like Yahoo! and Bing, plus Google, Ask.com, Gigablast -Search services maintain search engines—programs that users can use to ask questions or use keywords to find information -Databases of search engines are compiled using software programs called spiders (crawler, bots, agents) (Spiders crawl through the World Wide Web, Follow links from one page to another, Index the words on that site, A search never covers the entire web, Search engines differ in what they cover)
Connecting - Wired or Wireless?
• Physical connection to Internet — wired or wireless? • Telephone [dial-up] modem • High-speed phone line — DSL, T1/T3 • Cable modem • Wireless — satellite and other through-the-air links
Automatic Delivery of Information
• Push technology: Software that automatically downloads information to personal computers. • Webcasting: Sending users customized text, video, audio on regular basis. • RSS newsreaders (RSS aggregators): Programs that scour the web, sometimes hourly, sometimes more frequently, and pull together in one place "feeds" from several websites. RSS is based on XML, or extensible markup language, a web-document tagging and formatting language that is an advance over HTML and that two computers can use to exchange information.
Benefits of Networks
• Share peripheral devices, such as printers, scanners, disk drives • Share software • Share data and information • Better communications • Accessing databases • Centralized communications • Security of information, because of improved backup systems
File Transfer Protocol (FTP)
• Software standard for transferring large files between computers, including those with different operating systems • You can also transfer files from an FTP site on the Internet to your PC • FTP sites offer many free files • FTP sites may be either public or proprietary • You can download using your web browser or FTP client programs, such as Fetch, Cute, FileZilla, and SmartFTP
Network Linking Devices
• Switch — Device that connects computers to a network; sends only to intended recipients; operates back and forth at the same time. • Bridge — Interface device that connects same type of networks. • Gateway — Interface device that connects dissimilar networks. • Router — Device that directs messages among several networks, wired or and/or wireless. • Backbone — Main Internet highway that connects all networks in an organization; includes switches, gateways, routers, etc. • NIC (Network interface card) — inserted in a slot on the motherboard, enables computer to operate as part of a network. • NOS (network operating system) — the system software that manages network activity.
Narrowband (Dial-Up Modem)
• Telephone line = narrowband, or low bandwidth, low speed • Dial-up connection — use of telephone modem to connect to Internet (used mostly in rural areas on POTS, or plain old telephone system)
HTML (Hypertext Markup Language)
• The "markup" language used in writing and publishing web pages • Set of instructions used to specify document structure, formatting, and links to other documents on the web • Hypertext links connect one web document to another
Malware
• There are many forms of malicious software — malware — that can harm a computer system, a common danger being viruses. • A virus is a rogue program that migrates through the Internet or via operating systems and attaches itself to different programs that spread from one computer to another, leaving infections. • The principal defense is to install antivirus software, which scans a computer to detect viruses and, sometimes, to destroy them.
Satellites
• Transmits data between satellite dish and satellite orbiting earth • Connection is always on • Requires Internet access provider with 2-way satellite transmission • User needs to buy or lease satellite dish and modem and have them connected
Telephony: The Internet Telephone
• Uses the Internet to make phone calls via VoIP (Voice over Internet Protocol) • Long-distance calls are either very inexpensive or free • With no PC, dial a special phone number to packetize your call for a standard telephone • Use with a PC that has a sound card, microphone, Internet connection with modem & ISP, and internet telephone software such as Skype and Vonage • Also allows videoconferencing
Portals
• Web: Starting points for finding information -A gateway website that offers a broad array of resources and services, online shopping malls, email support, community forums, stock quotes, travel info, and links to other categories • Examples: Yahoo!, Google, Bing, Lycos, and AOL • Most require you to log in, so you can -Check the Home page for general information -Use the subject guide to find a topic you want -Use a keyword to search for a topic
Wireless
• Wi-Fi—stands for "wireless fidelity" • Name for a set of wireless standards (802.11) set by IEEE • Transmits data wirelessly up to 54 Mbps for 300 - 500 feet from access point (hotspot) • Typically used with laptops and tablets that have Wi-Fi hardware
URL (Uniform Resource Locator)
• address for a web page • A character string that points to a specific piece of information anywhere on the web • A website's unique address • It consists of: -The web protocol, http:// -The domain name of the web server -The directory name or folder on that server -The file within the directory, including optional extension
E-commerce
• conducting business activities online • has led to showrooming, the phenomenon in which shoppers browse for products in stores, only to buy them from an online rival, frequently at a lower price. -B2B is business-to-business e-commerce. -Business-to-consumer commerce, or B2C, is the electronic sale or exchange of goods and services from the companies directly to the public, or end users (e.g., online banking, online shopping, online stock trading). -Consumer-to-consumer commerce, or C2C, is the electronic sale or exchange of goods and services between individuals (e.g., auctions).
