APCSP Unit 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

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

Decimal system

number system we use in our everyday lives. It has ten digits, 0-9

Binary System

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

ASCII

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

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 Cipher

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

Symmetric encryption

The same key is used to encrypt and decrypt

Public Key encryption

a type of asymmetric key encryption. There’s on key that encrypts the informational and there is a different key that decrypts the information