1.3.1 Compression, Encryption and Hashing

Question 1

lossy compression

Answer 1

• permanently removes data
• so not able to recreate original file
• reduced quality
• smaller file size
• less buffering

Question 2

lossless compression

Answer 2

• rewrites original data in a more efficient format
• able to recreate the original file
• keeps original quality
• more buffering

Question 3

run length encoding

Answer 3

• reliance on consecutive pieces of data/characters which are the same/repeated
• if there is no repetition => less reduction in file size

Question 4

dictionary encoding

Answer 4

• frequently occurring pieces of data/groups of characters replaced w/ indexes
• dictionary is used => see which indexes match with groups of characters

Question 5

encryption

Answer 5

• keeps data secure when being transmitted
• data is scrambles so that if it is intercepted, it can’t be understood

Question 6

asymmetric encryption

Answer 6

• 2 different keys: public key for encryption, private key for decryption
• algorithms involve more processing than symmetric algorithms
• often used when exchanging data

Question 7

symmetric encryption

Answer 7

• the same private key for encryption/decryption
• if the key is intercepted during the key exchange, then communications can be intercepted and decrypted
• best suited when the same person is encrypting/decrypting eg. backing up data

Question 8

hashing

Answer 8

an input/key is turned into a fixed size value