runestone academy ap csp unit 6

Internet

* network of networks in which host computers are connected by routers
* governed by the Internet Protocol Suite
* based on open *standards*, enabling it to grow exponentially

protocol

system of rules that govern the behavior of a system

SMTP/POP

system of rules that govern email services

TCP/IP

routes messages between the clients & servers finding a path from the sender to the receiver

SSL (Secure Socket Layer)

protocol that establishes an encrypted link between a web server & a browser.

HTTP

* system of rules that govern the WWW application
* ensures secure, trusted, encrypted communication over the Internet

World Wide Web (WWW)

Internet application that is based on HTTP

URI (Uniform Resource Identifier)

uniquely identifies a resource on the WWW

HTML

language used to code Web pages

digital divide

* gap between those who have access to the Internet & computers with those who do not
* usually affected by socioeconomic, geographic, or demographic characteristics

bandwidth (throughput)

* rate at which data is downloaded/uploaded in a network
* measured in bits per second, kilobits per second, or megabits per second

latency

* measure of the amount of time it takes for a piece of data to reach its destination
* measured in milliseconds

ping

networking utility used to measure latency on the Internet/reachability of a host

traceroute

networking utility used to trace the route of & measure delays of packets moving through the Internet

broadband

high speed Internet service that is always on, typically through cable/DSL modems

Internet Service Provider (ISP)

company that provides customers with Internet access

network

group of 2 or more computers linked together

routing

The process of finding a path from sender to receiver.

router

transmits data between 2 different networks

enterprise-level router

connects the ISP to the core Internet backbone routers

home router

connects local devices to a cable modem

cable modem (DSL modem)

connects a home to an Internet Service Provider (ISP)

local area network (LAN)

connects computers within a small area i.e. home/school

wifi (wifi network)

uses radiowaves to connect devices

wide area network (WAN)

connects devices over a broad geographic region

internetwork (internet \[small “i”\])

collection of disparate networks that are connected together via routers

ethernet

uses wires to connect computers

fault-tolerant network

continues operating in the event of failure of 1 or more of its components

circuit-switched network

contains a dedicated channel between A & B

packet-switched network

contains no sustained connection between A & B

redundancy

* The inclusion of extra components that can be used to mitigate the failure of a system if other components fail
* Network redundancy can be accomplished by having more than 1 path between any 2 connected devices

firewall

barrier that protects a network from unauthorized access

computing system

group of computing devices & programs working together for a common purpose

client

computer/software application that requests services from a server located on the internet i.e. web browser

server

host that provides a service i.e. Google’s Gmail service

host

computer that is connected to the Internet i.e. servers

port

memory location in a server’s RAM that is connected to software that listens for incoming requests

scalability

capability of a system to change in size & scale to meet new demands

packet

* fixed collection of data used by TCP/IP protocol to transmit data across the Internet
* contains routing data & content of the message

packet switching

Method in which information is transmitted through the Internet via breaking the information into packets & routing it independently from source to destination

packet sniffer

* Software used by network administrators to monitor data being transmitted over a network.
* Can be used to steal email messages and other information

Application Layer

* Composes a message & passes it to the Transport Layer
* Receives other messages passed on from the Transport Layer

Transport Layer

* Splits a message into packets, adds TCP headers to number the packets, & sends it to the Internet Layer
* Receives packets from the Internet Layer, places them in order, & passes it to the Application Layer when all is received

Internet Layer

* Adds the destination IP address to each packet & passes it to the Link Layer
* Receives packets from the Link Layer & checks to see if it is their IP address
* If it is, it passes it to the Transport Layer
* If not, it sends it back to the Link Layer to pass on to another IP address

Link Layer

* Sends the individual packets to the Link Layers of other IP addresses
* Receives packets from other addresses & passes them to the Internet Layer

IP address

String of numbers separated by periods that identifies each computer using Internet Protocol to communicate over a network

IPv4

32-bit dotted decimal notation IP address

IPv6

128-bit hexadecimal notation IP address

domain name

hierarchical name that identifies a domain & institution on the Internet i.e. .com, .edu, .gov

hostname

domain name that is associated with an IP address

Domain Name System (DNS)

Internet service that translates domain names into IP addresses

routing table

used to look up a domain name & find its corresponding IP address

cryptography

* “secret writing”
* art & science of writing secret messages

public key cryptography

uses two keys: a public key known to everyone & a private/secret key known only to the recipient of the message.

plaintext

unencrypted, readable message

ciphertext

unreadable, secret message

encryption

process of using a secret key to convert plaintext into ciphertext

decryption

process of using a secret key to convert ciphertext into plaintext

encryption key

piece of secret data used by encryption & decryption algorithms

encryption algorithm

uses a secret key to encrypt messages

symmetric encryption

the same key is used for encryption and decryption

asymmetric encryption

separate but related keys are used for encryption & decryption.

diffie-hellman

* algorithm used to establish a shared secret between two parties
* primarily used to exchange a symmetric key among 2 parties

cipher

system for creating a new alphabet/secret messages

substitution cipher

letters from a ciphertext alphabet are substituted for letters in a plaintext message systematically

Caesar cipher

shifts the alphabet by 3 letters to create cipher alphabet, substituting plain letters with shifted letters

Vigenere cipher (polyalphabetic substitution)

uses multiple alphabets to encrypt a message

transposition cipher

letters are rearranged in a plaintext message without substitution

frequency analysis

The counting of the occurrence of letters in an encrypted message in an effort to discover patterns that might reveal its encryption key

one time pad

Perfect (unbreakable) encryption that is achieved by using a single-use random polyalphabetic key that is as long as the message itself

key exchange problem

problem of sharing a secret cryptographic key between Alice and Bob without Eve being able to intercept it

RSA (Rivest-Shamir-Adleman)

* Cryptosystem used for public-key encryption
* Widely used for securing sensitive data sent over an insecure network like the Internet.
* Based on a one-way function (m^e mod N→c)

strong password

A series of characters that is easy for a user to remember, but would be difficult for someone else to guess based on knowledge of that user.

bug

error in computer hardware/software

syntax error

An error that results from a violation of a programming language’s grammatical rules.

semantic error

error in which the program is not working as it is designed to work.

run-time error

mistake in the program that occurs during the execution of a program.

debugging

process of removing errors from computer hardware/software

malware

Software intended to damage a computing system or to take partial control over its operation.

malware scanning software

Software that helps protect a computing system against malware infections.

ransomware

malware that encrypts & locks computer systems until a ransom is paid.

Trojan horse

a malicious program that disguises itself as a useful program that unsuspecting users download.

virus

* a malicious program that can copy itself & gain access to a computer in an unauthorized way
* often attach themselves to legitimate programs and start running independently on a computer.

worm

a malicious program that spreads by itself through networks of computers

phishing

technique used to trick a user into providing personal information usually through email.

rogue access point

Gives unauthorized access to secure networks wirelessly.

trust model

The use of a trusted third party to verify the trustworthiness of a digital certificate.

certificate authority

entity that issues digital certificates.

digital certificate

data packet that certifies the holder of a public key.

keylogger

Program used to record every keystroke made by a computer user in order to gain fraudulent access to passwords & other confidential information

biometrics

use of unique physical characteristics i.e. finger prints, face recognition for identification

multi-factor authentication (MFA)

Method of computer access control in which a user is only granted access after successfully presenting several separate pieces of evidence i.e. knowledge, possession, and/or inherence

function

procedure that computes & returns a value

local variable

variables that are declared & exist only within a procedure or function (scope)

crowdsourcing

practice of obtaining input/information from a large group of people via the Internet