Unit 8 APCSP Voacb

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 our 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

ASCII

the standard protocol for encoding text information as bits. The ASCII 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

cyptography

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)

public key encryption

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