Ap Computer Science Principles: Internet Flashcards
What is a bit?
a single unit of data that can only have one of two values (such as a 1 or 0)
What is a byte?
Eight bits (e.g.10110101)
What is bandwidth?
the transmission capacity of a system (measured by the amount of data (measured in bits) that can be sent in a specific amount of time)
What is latency?
time between the transmission and the receipt of a message
What does an ethernet cable use? What are its features?
It uses electricity to send bits. Best for close distances, but cheap and has potential signal loss
What does an fiber optic cable use? What are its features?
It uses light to send bits. Best for far distances, fast, and lower potential signal loss, but expensive and hard to work with
What is a web browser?
An app used to access web pages
What is an URL? Uniform Resource Locator
An address for accessing specific web data located on a server
What is a DNS server? Domain Name System server
A computer or computers hosting data for other to access
What is HTTP? HyperText Transfer Protocol
Language used to communicate between web browsers and servers
What is HTML?
HyperText Markup Language: language used to tell a web browser how to make a page look
What two components does HTML decide separately?
(1) the text on the web page(2) each separate picture and video(a separate HTML code for every one of those)
What are the steps of accessing a web page?
(1) Open web browser(2) type in URL or other(3) HTTP code [get () request] is sent to DNS(4) DNS returns HTTP containing HTML files to make up page
What is a cookie (computer science-wise)?
What websites use to remember who you are (like an ID card)
How does sending information on web browsers work?
(1) Input information (like google search or login)(2) Information sent in HTTP "post" request(3) Goes to domain name server(4) Pertaining data sent back(5) In returning data cookie is attached for website to remember user(6) Next time server logs on when he sends information the cookie will be attached so domain server will know who it is
What is SSL (Secure Sockets Layers) and TLS (Transport Layer Security)?
A layer of security wrapped around a user's communications to prevent snooping or tamperingand the Successor to SSL
How does one know is SSL/TLS is active on their browser?
There would be a lock sign next to the URL
What is HTTPS? HyperText Transfer Protocol Secure
Ensure HTTP requests are secure and protected
Why are digital certificates important in internet safety?
Digital certificates (issued by certificate authorities) ensure that the information being sent by a certain website is legit and also allows a secure SSL/TLS connection
What are the three things that make up a URL?
Protocol: standard for communication between browsers and servers (usually http or https)domain name: the name of the server that hosts the datapath: the location of the data in a hierarchy of folders on the server
How is the Internet designed to be redundant? Why?
There are multiple pathways among the physical connections of the Internet; If one or more pathways break down, there would still be another way to transmit a message from sender to receiver
How does Internet redundancy impact fault tolerance (the ability to work around problems) and scalability?
(1) By increasing the number of possible pathways. (2) It increases the ability to function even as size changes by making the internet more expansive to more devices and people
How is the Internet hierarchal?
Two internet addressing systems are domain named and IP addresses. They work like a postal system, getting more specific in each addressed step.
What are nodes?
Connections points that link pathways
How are domain names and IP addresses related?
People use domain name to visit websites, and computers translate those domain names into IP addresses to locate and send data
What is a root domain, primary domain, and subdomain?
Root domains: top level (e.g. .gov, .edu, .org)Primary domain: Segment after root (In the URL code it comes before (e.g. about.berkeley.com, about berkeley is the primary domain)Subdomains: Subsections of the primary domain (e.g. the "about" section in the above address)
What is an IP address?
Unique numerical addresses assigned to every device on the Internet.
What is IP (Internet Protocol)?
An addressing system that finds paths to distant computers
What is IPv4?
An IP address made up of four bytes
What is IPv6?
An IP address solution to the limit of the iPv4. It is made up of 128 bits summarized by hexadecimal
What is TCP? Transmission Control Protocol
A reliable transmission system that sends and tracks binary sequences of data that are split into small packets sent separately
What are packets?
Small chunks of one whole data sent individually throughout the web on their own path
What are routers?
Connection points that route traffic between subnetworks of the Internet. They choose the cheapest, most direct path for packets to travel.
What are application layer protocols?
highest level of abstraction because they manage how data is interpreted and displayed (e.g. HTTP and DNS). Give meaning to bits sent by lower levels.
What are transport layer protocols?
manages breakdown and reconstruction of message into packets (e.g. TCP)
What are Internet layer protocols?
Manage the pathways that the data travel across networks. (e.g. IP)
What is an ISP? Internet Service Provider
Provides Internet connection
What is SMTP (Simple Mail Transfer Protocol)?
Standards used for directing mail around the internet
What organizations "control" the internet?
(1) IETF: Handles protocols approval and development(2) ICANN: Controls DNS and IP address(3) ISOC: In charge of IETF and other
What is a DoS (denial of service) attack?
Hackers overwhelm a website with too many requests that makes it crash
How does a DDOS attack work? Distributed Denial of Service
Hacker uses virus to take control of MANY computers. The infected network is called a botnet. The attacker then launches DOS attack from the infected computers (called zombie computers) to crash a website
What is phishing?
A spam e-mail purposed to hack
What are firewalls?
Limits the kinds of connections outsiders can make to your computer.
What is encryption?
Scrambling a message to make it unreadable to the unintended audience
What is brute force decryption?
Trying every single possible combination
What is public key encryption (a.k.a. RSA)?
A cryptographic system that uses two keys -- a public key known to everyone and a private or secret key known only to the recipient of the message.
What is the difference between symmetric and asymmetric encryption?
Symmetric: Same key used to encrypt and dencryptAsymmetric: Uses public and private key