Chap 5.1 - The internet & its uses (Internet and WWW, digital currency) Flashcards
define internet
global network of interconnected computers
define World wide web
a collection of web pages accessed via the internet
difference between internet and WWW
-the Internet can function without the WWW but the WWW cannot function without the Internet
-the Internet is the infrastructure & the World Wide Web is a service built on top of it
does www relie on internet
yes
does the internet relie on www
no
how do you access a web page
URl
What are in the website address
-domain host
-domain name
-domain type
-country code
what does URl stand for
Uniform Resource Locator
why is it called URL
Uniform- consistent format
Resource- web page, pdf, pic etc
Locator- finder
what is the format of a URl
protocol:// website address /path /file name
what is the domain host
www
what is the domain name
website name
what is the domain type
eg. .com , .org
what is path
web page directing to file
what is file name
item on web page
is www used for apps
no
what is index page
first page of a website
what is hyperlink
text or picture that links to a website
what is address bar
where you type URl
what is a web
interconnected websites
What are the protocols
-https
-http
What does http mean
HyperText Transfer Protocol
What does https mean
HyperText Transfer Protocol secure
what are the features of http (4)
-date transmission in plain text
-can intercept data or eavesdrop
-used for website without sensitive date
-faster than https
What are the features of https (3)
-date transmissions are encrypted using an encryption algorithm (secure)
-protected against eavesdropping and data interception
-used for website with sensitive data
-have padlock symbol on website
how do you know a website is secure
-will have padlock symbol
-https
2 encryption algorithms
SSL and TLS
What does SSL stand for
Secure Socket Layer
Who issues encryption algorithms
Certificate authority (CA)
What does SSL do
-has a public key for encryption
-server has the only private key used to decrypt data
-key is encrypted
What is web browser
-software that connects DNS to locate IP address
-display web pages by rendering HTML
What is DNS
Domain name server
What are the functions of web browser
-store websites as bookmarks
-keep history of website user visited
-can switch between websites
-use tabs to open multiple web pages
-data stored as cache
-use hyperlinks
-use cookies
-uses address bar
-have a home page
What is the first DNS
ISP
What is ISP
internet service provider
How does a browser look up a web page using DNS
-user opens browser, types URL and browser asks DNS (1) to map URL to IP address
-If DNS (1) don’t have, request sent to DNS (2) which maps URL to IP and sends it to DNS (1)
-DNS (1) put IP and associates URL to it’s database/ cache
-Website server sends HTML files and IP address to comp and required pages are downloaded. Browser displays content by rendering HTML
What does HTML files do when the browser interoperates it
structures content
what is forward look up
DNS - IP
What is reverse look up
IP - DNS
what is a cookie
text file sent to user’s browser to track user preferences
what are persistent cookies
cookie stored in user’s hard drive
what are session cookies
temporarily stored cookie on user’s computer
similarities between session and persistent cookies
-stores user’s preferences
-saves user’s items in a virtual shopping cart
differences between session and persistent cookies
session:
-stored in temporary memory of comp
-new cookie created when revisiting website
-don’t collect personal info
-deleted once user leaves website
-doesn’t identify user
persistent:
-stored in hard drive of comp
-stored until expiry data or user deletes it
-has personal details that logins user when revisiting website
-remain after browser closes
-identifies user when they revisit website
-allows progress on games/ quizzes to be stored
What is digital currency
currency managed, stored & exchanged digitally & issued by a central authority
what is cryptocurrency
digital currency that uses cryptography for security based on a blockchain and lacks a central authority
same btw digital currency & cryptocurrency
-both are digital
-stored in digital wallets & transacted through internet
-potentially accessible to anyone with internet access
-experience fluctuation in value
diff. btw digital currency & cryptocurrency
crypto:
-
How does cryptocurrency work
block chaining
what is the problem with centralisation
maintaining confidentiality and security
what is a block chain
-decentralised database that stores transactions
-consists of interconnected computers with no central server
-uses cryptocurrency to monitor all transactions
what is the name of the first block in a block chain
genesis block
what does all blocks in a block chain contain
-data (info. abt transaction)
-hash value
-previous hash value
how does block chaining remove security issues/ changed blocks
-each block has a unique hash value which changes when tampered with
-the next block previous hash value does not match to the changed has value
-hash value link with other blocks are broken
-next block and beyond, transaction with following blocks, are invalid
what happens when a new transaction is made
new transactions- new block- new hash value with timestamp
hash value is unique to each block, timestamp identifies when event took place
what is the previous hash value of genesis block
00 00
what is proof of work
10 mins necessary to check a block before it is added or a transaction happens
who are miners
those who do proof of work and get commissions in cryptocurrency for them
how do you tackle a block chain
need to tackle all blocks at the same time
what happens if data changes
hash value changes
what does a block show
a transaction had taken place
