Test 1 Flashcards
the amount of data that can be carried over a data network or connection in a fixed amount of time; higher=more data, expressed in bps
bandwidth
a network of zombie computers that can be remotely controlled by a hacker
botnet
the act of using social media to create fake profiles, especially for the purpose of luring unsuspecting victims into online relationships
catfishing
a protocol in which a _____ server assigns IP addresses to computers when they join a network. computer’s IP is not fixed, but can be different every time a computer joins the network
DHCP (dynamic host configuration protocol)
a system for mapping human-friendly names to numeric IP addresses. DNS translates the name into the corresponding IP address. like directory assistance for the internet
DNS (domain name system)
an incident in which a user or organization is deprived of the services of a resource that they would normally expect to have. can target a person or company and are costly. can be politically motivated.
DoS (Denial of Service attack)
computer becomes infected just by visiting a website which contains malicious code, vulnerable servers are searched for. cybercriminals inject their malicious code onto web pages. affects if you are unpatched
drive by download
the number of legs (or hops) a particular packet takes as it moves from its source to its destination. aka number of routers a packet passes through on its journey
hop count
protocol for moving hypertext files and other info across the internet, requires browser on one end and web server on the other. uses tcp/ip services and is most important protocol for world wide web
http (hypertext transfer protocol)
standard internet protocol that routes data packets across multiple nodes and networks on a best effort basis and is unreliable
IP (internet protocol)
standard way of identifying a computer that is connected to the internet
IP address
hijacking and fraudulent use of another person’s personal information without that person’s knowledge
identity theft
the amount of time it takes for a packet of data to get across a network from one point to another
network latency
a unit of data sent across a network, contains destination address, sender’s address, error-control info, and data. layout determined by protocol
packet
use of counterfeit emals and fraudulent websites to fool recipients into disclosing personal financial data such as credit card numbers, usernames and passwords, and social security numbers
phishing
standard set of rules that govern how computers and electronics communicate with one another, define a messages format and how they are exchanged
protocol
intermediate server that sits between clients and the servers those clients use. accepts requests from clients and transmits those requests to the server. prevents clients from accessing prohibited servers, etc.
proxy server
kind of extortion via software, in which a Trojan horse running on a computer will encrypt some files, only to be returned for money
ransomware
software that hides the real screen of a computer to conceal the presence of other intrusive software. may hide some data so its not visible to the user
rootkit
device that interconnects multiple computer networks, read the address info on data packets, which are then forwarded in the appropriate direction. assoc. with IP
router
malware that preys on naïve users, usually reports some nonexistent problem and convinces user to buy a software to “fix” it
scareware
gaining access to systems or data by exploiting human psychology, rather than hacking
social engineering
unsolicited junk messages, typically email, sent indiscriminately to many users at once
spam
a particular, designated victim or organization is targeted with an email customized for them, based on information the sender has gathered
spear phishing
software that gathers information about a computer user and then transmits this info to an external entity without the knowledge or informed consent of the user
spyware
standard internet protocol that converts messages into streams of packets at the source, and reassembles streams of packets
TCP (transmission control protocol)
deceptive program that is presented as somewhat desirable, but is actually destructive with a malicious function
Trojan horse
computer program that can reproduce by changing other programs to include a copy of itself. parasite program (needs another program to survive). requires a person/human contact to spread it
virus
software program capable of reproducing itself and spreads automatically from one computer to the next over a network, generally taking advantage of security flaws. can spread once in a network without further human interaction
worm
computer attached to the internet that has been comprised by a computer virus or Trojan horse so that it performs malicious tasks directed by the hacker. owners of these computers are often unaware it is even infected
zombie
transforms infinites set of values to a finite set. sample analog input signals and convert to digital output signal. series of numbers representing the amplitude of the original signal as measured periodically (quantizing)
analog to digital converter
world wide standard for the code numbers used by computers to represent all characters
ASCII (American standard code for information exchange)
device or program that protects a network or individual computer from unauthorized external users. blocks certain types of traffic
firewall
standard language for creating webpages
html
company that sells access to the internet
ISP (internet service provider)
connects computer in a relatively small area
LAN (local area network)
control information on a packet needed by the network to deliver the user data
packet header
data transmission method in which data is transmitted in packets through a network to a remote location
packet switching
a set of up to 256 colors used in an image
palette
often referred to as a dot, “dots per inch” short for picture element. make up an image
pixel
connection point or interface and an external device
port
process of limiting a value to one of a fixed number of values
quantization
field in a packet header for some protocols, identifying the data contained in the payload
sequence number
universal character set or wide-body ASCII that can represent all the characters in the world’s written languages
unicode
global address for documents and other resources on the world wide web. first part indicates what protocol to use, second part indicates the IP address or domain name
URL (uniform resource locator)
a computer network covering a large geographical area usually interconnecting two or more LANs
WAN (wide area network)
abbrev. dns
domain name system
abbrev. http
hypertext transfer protocol
abbrev. ip
internet protocol
abbrev. isp
internet service protocol
abbrev. LAN
local area network
abbrev. RFC
request for comment
abbrev. tcp
transmission control protocol
abbrev. URL
uniform resource locator
how many bits in a kilobyte
8x1024
what is a socket
ip address+tcp port
computer to program
connection you use
internet vs. world wide web?
the internet is a collection of connected networks that can communicate with each other using TCP/IP, while the world wide web is a global web of linked information in various formats. its built using services of the internet, but those services are also used for separate things (email, voiceover). primary protocol of the web is HTTP
format of an IP address?
x.x.x.x where x is a number between 0 and 255
what type of images should use jpeg?
photos, images with complex color schemes
what type of images should use gif?
line art, images with large areas of single color
cookies: what creates?
when created?
where saved?
when sent from browser to web server?
created by web server
created when you visit a webpage
saved in browser
sent from browser to web server when you visit the site again
virus vs. worm
worms do not need anymore human interaction to spread once they have infected a network (it spreads automatically). viruses require people to spread them (not on purpose)
zombie computer: what is it?
how does it get this way?
how is it controlled?
what can it be used for?
it is a computer that has been compromised by malware that performs various malicious tasks
it is infected by a virus or Trojan horse to get this way
it is controlled by the hacker
it can be used for dos attacks or sending a spam email
3 components of the google search and explanation
the crawl: reads all the web pages it can find and follows links from those pages to find others
the index: builds a database of the contents of those pages
the query processor: when a user submits a request, it used the info in the index and a complex set of rules to construct the best response
responsibilities of client vs. server
client: handle user interface, translates requests into protocol, send request to server, wait, translate response into readable results, present them
server: listen for client’s request, process it, return results back to the client, maintain secure and important information
ip vs tcp vs http
ip: unreliable, sees that packets are routed across multiple nodes and networks
tcp: reliable, uses ip, converts messages into streams of packets at the source, then reassembles them into messages at the destination
http: uses tcp/ip to move hypertext files and other info across the internet.
how is an image turned into a set of numbers
-how does # of pixels and colors used affect: A) # of bytes B) how closely the actual image is represented in the digital representation
the image is divided into pixels, which each get assigned a solid color which requires 3 bytes (each color has a number) or use a palette (256 colors in each, each pixel requires one byte).
A) more colors used means more bytes, 3 bytes per pixel, but if a palette of colors is used then only one byte is required for each pixel.
B) not enough colors in the palette-won’t match the original picture close enough, not enough pixels-will be able to see each individual pixel, the picture won’t be sharp enough
how can tcp reliably deliver a message over an unreliable ip network
when the large message is broken up into packets, these packets are numbered and sent.
-received packets are acknowledged
-unacknowledged packets are resent
-duplicate packets are discarded
at the destination the packets are reassembled into the original message
describe the Melissa virus: how did it work?
how was it spread?
what made it so effective?
the Melissa virus was sent via email
