csp vocab unit 4

Abstraction

simplifying complex things

ASCII

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

Binary Number System

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

Bit

shorthand for binary digit, is either a 0 or 1.

Caesar Cipher

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

Compression

reducing file size

Cryptography

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

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. It can reduce the size (number of bits) of transmitted or stored data. The ultimate foal of compression algorithms is to condense information (bits) into its most space-efficient, compact form for transmission or storage, and minimize any waste of space. Fewer bits do not necessarily mean less information.

Decimal Number System

the number system (base 10) we use in out everyday lives. It has 10 digits, 0-9.

Digital Information

data represented by bits

Hexadecimal Number System

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).

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. Compression has occurred that can reduce the number of bits stored or transmitted while guaranteeing complete reconstruction of the original data.

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. Compression has occurred that can significantly reduce the number of bits stored or transmitted but only allow reconstruction of an approximation of the original data.

Number Base

defines how many digits are in the number system, and the base of the exponent for each place value in a number. They are used to represent data

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.

Pixel Image

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

Public Key Encryption

a type of asymmetric key encryption. There’s one key that encrypts the information (public key) and there is a different key that decrypts the information (private key).

RGB Color Encoding

allows us to encode colors such as numeric data. It defines the amount of Red, Green, and Blue light in a pixel.

Symmetric Encryption

same key encrypts

Webimage

provides a JavaScript API that lets us add images to our programs and manipulate their pixels.