AP Comp Sci P Semester 2 Vocab

Moore's Law

a predication made by Gordon Moore in 1965 that computing power will double every 1.5-2 years, it has remained more or less true ever since

Caesar Cipher

a technique for encryption that shifts the alphabet by some number of characters

Cipher

the generic term for a technique (or algorithm) that performs encryption

Cracking Encryption

when you attempt to decode a secret message without knowing all the specifics of the cipher

Decryption

a process that reverses encryption, taking a secret message and reproducing the original plain text

Encryption

a process of encoding messages to keep them secret, so only "authorized" parties can read it

Random Substitution Cipher

an encryption technique that maps each letter of the alphabet to a randomly chosen other letters of the alphabet

Vigenère Cipher

a method of encrypting text by applying a series of Caesar ciphers based on the letters of a keyword

Computationally Hard

a "hard" problem for a computer is one in which it cannot arrive at a solution in a reasonable amount of time

Symmetric Encryption

a type of encryption where the same key is used to encrypt and decrypt the message

Asymmetric Encryption

used in public key encryption, it is scheme in which the key to encrypt data is different from the key to decrypt

Modulo (or mod)

a mathematical operation that returns the remainder after integer division

Private Key

the complementary key to a public key that is used to decrypt a message

Public Key

a value that can be used to encrypt a message; however, only when combined with a mathematically-related private key, can the message be decrypted

Phishing Scam

typically a thief trying to trick you into sending them sensitive information; including: emails about system updates asking you send your username and password, social security number or other things

DDoS (Distributed Denial of Service) Attack

typically a virus installed on many computers (thousands) activated at the same time and flood a target with traffic to the point the server becomes overwhelmed

Virus

a program that runs on a computer to do something the owner of the computer does not intend

Antivirus Software

usually keeps big lists of known viruses and scans your computer looking for the virus programs in order to get rid of them

Firewall

software that runs on servers (often routers) that only allows traffic through according to some set of security rules

SSL (Secure Sockets Layer) and TLS (Transport Layer Security)

an encryption layer of HTTP that uses public key cryptography to establish a secure connection

Callback function

a function specified as part of an event listener; it is written by the programmer but called by the system as the result of an event trigger

Event

an action that causes something to happen

Event-driven program

a program designed to run blocks of code or functions in response to specified events (e.g. a mouse click)

Event handling

an overarching term for the coding tasks involved in making a program respond to events by triggering functions

Event listener

a command that can be set up to trigger a function when a particular type of event occurs on a particular UI element

UI Elements

on-screen objects, like buttons, images, text boxes, pull down menus, screens and so on

User Interface (UI)

the visual elements of a program through which a user controls or communicates with the application

Debugging

finding and fixing problems in an algorithm or program

Data Type

all values in a programming language have a "type" - such as a Number, Boolean, or String - that dictates how the computer will interpret it

Expression

any valid unit of code that resolves to a value

Variable

a placeholder for a piece of information that can change

==

the equality operator (sometimes read: "equal equal"); used to compare two values, and returns a Boolean (true/false)

If-Statement

the common programming structure that implements "conditional statements"

Variable Scope

dictates what portions of the code can "see" or use a variable, typically derived from where the variable was first created

Global Variable

a variable that can be used and updated by any part of the code; typically derived from the variable being declared (created) outside of any function, object, or method

Local Variable

a variable that can only be seen, used and updated by code within the same scope; typically, this means the variable was declared (created) inside a function -- includes function parameter variables

Syntax errors

things you misspelled or wrote in such a way the computer doesn't understand what you're trying to say; usually the computer spits out an error message of some kind that is a clue about what it can't understand

Logic errors

the program runs but doesn't do what you think it should; can be tricky to fix because there might not be an error message

Concatenate

to link together or join. Typically used when joining together text Strings in programming (e.g. "Hello, "+name)

String

any sequence of characters between quotation marks (ex: "hello", "42", "this is a string!")

Conditionals

statements that only run under certain conditions

Selection

a generic term for a type of programming statement (usually an if-statement) that uses a Boolean condition to determine, or select, whether or not to run a certain block of statements

Boolean

a single value of either TRUE or FALSE

Boolean Expression

in programming, an expression that evaluates to True or False

Iterate

to repeat in order to achieve, or get closer to, a desired goal