encryption and compression

Question 1

What is compression and why use it

Answer 1

Reduces the size of a data file

Uses less storage

Faster download

Question 2

Lossy compression

Answer 2

Lossy compression maximises the reduction in file size

But there may be a loss of quality

Store fewer data points

Store using simpler code numbers

Sounds will be sampled less often pre seconds and recorded with less precision

Images will be low resolution and low colour depth

Question 3

Lossless compression

Answer 3

Sometimes possible to compress data with no loss of data quality, but the reduction in size may be less

Run-length encoding

Dictionary compression (colour palette)

Question 4

What is encryption and why use it

Answer 4

Encrypting a message means disguise it so it can’t be read by anyone who doesn’t have the key

Decrypting means returning an encrypted message to readable form

Necessary to keep personal and financial details safe when sending over the internet

Question 5

Symmetric encryption

Answer 5

The same key is used to encrypt and decrypt