Unit 2 Communication And Internet Technologies

• Most reliable • Data is sent one bit at a time down a single wire • Bits are kept separate and low chance of data being skewed • Used in USB

• Data is sent multiple bits at a time down multiple wires • Quite fast used integrated circuits • Used short distance else high chance of data being skewed • Data sent from computer to printer

• Synchronous- data transmitted as a continuous stream, ensures data send and received are in sync • Asynchronous- data transmitted in an agreed pattern using control bits, stops data from being mixed up

• Asynchronous serial data transmission • When plugged in computer, automatically detected, device driver is loaded and communication can occur Advantages- • Can’t be inserted incorrectly • Supports different transmission speeds • Backward compatible • Robust and portable

-Uses parallel data transmission -IC require high speed Internal clock used to correct timing of data making it synchronised -Uses many wires

Simplex: -Data transmission in only one direction Duplex -Data transmission both directions simultaneously Half-duplex -Data transmission both directions but not at the same time

• More accurate over long distance • Less chance of interference that will skew or distort data • Data will arrive in order • Cheaper to purchase/install/maintain

• Faster transmission speed • Can send lots of data at one go • More efficient short distances

• Phishing • Pharming • Spyware • Hacking • Dos • Malware • Viruses • Worm • Rootkit • Backdoor

Anti-spyware • Scans computer for spyware • Removes/quarantines any spyware found • Prevent spyware from being installed Onscreen keyboard • Key-logger can’t collect data of key press • Can’t relay useful info to 3rd party 2 Factor Authentication • Extra data sent to device • Harder for hacker to obtain data • Data has to be entered into same system if entered from remote location not accepted Firewall • Can be software or hardware based • Monitors incoming and outgoing traffic • Allows criteria to be set • Blocks access to signal that do not meet criteria • Restricts access to specific applications • Can also blacklist certain IP addresses and close certain ports

Anti-virus • Scans computer for viruses daily • Has a record of known viruses • Removes/Quarantines any virus found • Warns user of virus • Checks data before downloaded • Prevents download of virus found Firewall/Proxy server • Monitors incoming and outgoing traffic • Allows setting of criteria • Checks if traffic meets criteria • Blocks traffic that does not meet criteria • Can also blacklist certain IP addresses and close certain ports

Firewall/Proxy server • Monitors incoming and outgoing traffic • Allows setting of criteria • Checks if traffic meets criteria • Blocks traffic that does not meet criteria • Can also blacklist certain IP addresses and close certain ports Passwords • Use long and more random passwords • Change it regularly • Lock after a set attempts Biometrics • Data needed to enter is unique to individual • Hard to replicate • Lock after set attempts 2 Factor Authentication • Extra data sent to device • Hard for hacker to obtain • Data entered needs to be in the same system, if attempted from remote location it’s not accepted

Phishing − Legitimate looking email sent to user − encourages user to click a link that directs user to a fake website − User encouraged to enter personal details into a fake website // designed to obtain personal details from a user Pharming − Malicious code/malware is downloaded without users’ knowledge − That re-directs user to fake website (when legitimate URL entered) − User encouraged to enter personal details into a fake website − Designed to obtain personal and sensitive details from a user

• Allows user to view web pages • Translates HTML into human readable language • Allows user to bookmark • Allows multiple features • Stores cookies • Has browsing history • Allows file to be downloaded from web • Manages HTTP/HTTPS protocols

• Provides access to internet for customer • Can determine maximum bandwidth available for customers • Monitors volume of data downloaded by customers • Can provide an IP address for the customer

• Hypertext Transfer Protocol Secure • It is a protocol/rules which must be followed when transmitting data over the World Wide Web • Secure version of HTTP • Secures website and data • Uses TSL/SSL, methods of encryption

• Hypertext Transfer Protocol - It is a protocol/rules which must be followed when transmitting data over the World Wide Web

-Hyper text markup language, markup language Structure • Placement of text/image • Margins • Line break • Padding Presentation • Font colour • Font style • Background colour • Image size • Border properties

• Can easily edit the style of the web page • So CSS can be used to create a template • Can add new content and apply same style easily • Can re-use the presentation style for other websites

-Small packets of data that are stored by the web browser -Store a customer’s password -To store a customer’s credit card details -So they do not need to be re-entered in future −To track what the customer has viewed on the website -So can send them adverts that match their preferences • Web server sends cookie file to users browser • Users payment details stored in encrypted text file • Cookie file stored by browser on users HDD/SSD • When website is revisited, web server requests cookie file • User does not see what info is stored • User feels their privacy affected • A profile could be built about user • Identity exposed • Sensitive info stored in cookies could be intercepted

• Unique serial number assigned to each device • Assigned by manufacturer • Consists of hexadecimal numbers • First half is manufacturer ID • Second half is serial number • Normally 64 bits in length

• Assigned by network • An IP address can be changed if dynamic • IP address has 8 groups of values • IP address is 128 bits • Does not contain serial number • IP given to every device by ISP that is connected to the internet

− Provides an interface − Loads / opens / installs / closes software − Manages the hardware // manages peripherals // spooling − Manages the transfer of programs into and out of memory − Divides processing time // processor management − Manages file handling − Manages error handling // interrupt handling − Manages security software − Manages utility software − Manages user accounts − Multitasking − Multiprogramming // time slicing − Batch processing