APCSP Vocab 8

abstraction

Managing complexity by "abstracting away" information and detail, in order to focus on the relevant concepts.

digital information

Generally comprises data that is created by, or prepared for, electronic systems and devices such as computers, screens, calculators, communication devices and so on, and can be stored on those devices or in the Cloud

number system

Defines how we represent numbers. It defines which digits we can use, and what value each position (place value) in a number has.

number base

Defines how many digits are in the number system, and the base of the exponent for each place value in a number.

decimal number system

The number system we use in out everyday lives. It has 10 digits, 0-9.

binary number system

Number system that has 2 digits, 0 and 1. This is how computers represent numbers at the base level.

bit

"binary digit". A bit is a single digit in a binary number. A bit can either be 0 or 1.

ASCII

The standard protocol for encoding text information as bits. The ASCII table assigns a unique binary number to every text character.

pixel image

An image can be represented as a grid of values. Each value encodes the color at that position in the image.

pixel

Images are made up of pixels, which are essentially a grid of values. Each value, or pixel, encodes the color at that position in the image.

hexadecimal

The hexadecimal number system is the Base 16 number system. It is a number system that only uses 16 digits (0 1 2 3 4 5 6 7 8 9 A B C D E F)

hexadecimal number system

Number system that has 16 digits 1 - 9 and A - F.

RGB color encoding

Encodes colors as numeric data. It defines the amount of Red, Green, and Blue light in a pixel. Each color channel can have a value between 0 and 255.

image filter

A procedure that applies a particular function to an image's pixels to change its appearance

data compression

The process of encoding information, using fewer bits than the original representation. We can use algorithms to compress the data to use less bits for storage and then decompress it when we want to view it again.

lossless compression

Involves no loss of information. If data have been "losslessly" compressed, the original data can be recovered exactly from the compressed data after a compress/expand cycle.

lossy compression

Throwing away some of the data to save space. We can throw away a lot of data without any noticeable difference from the original.

cryptography

Scrambling digital information into an unreadable form. Only those with verified authority (password, key, etc) can unscramble it to read it.

caesar cypher

An encryption method in which each letter of the message is shifted by a certain amount, called the key

symmetric encryption

The same key is used to encrypt and decrypt (e.g., Caesar, Vigenere)

asymmetric encryption

One key encrypts, a different key decrypts.

public key encryption

Type of asymmetric key encryption. There’s one key that encrypts the information and there is a different key that decrypts the information.

key

A shared secret that allows the recipient to convert ciphertext into plaintext.

decryption

The conversion of encrypted data into its original form.