1.3.1 Compression, Encryption and Hashing

What is compression?

s the process used to reduce the storage space required by a file, meaning you can store more files with the same amount of storage space.

How does compression help in transferring files over networks?

The larger a file, the longer it takes to transfer and so compressing files increases the number of files that can be transferred in a given time.

What are the 2 types of Compression?

Lossy-compression reduces the size of a file while also removing some of its information.
Lossless-n reduces the size of a file without losing any information. OG file can be recovered

What is Run Length Encoding?

a method of lossless compression in which repeated values are removed and replaced with one occurrence of the data followed by the number of times it should be repeated.
Best used in cases with consecutive repetition; if there is little repetition, this doesn't offer a great reduction.

What is Encryption?

The processing of scrambled data so that only authorized people can view the contents.

Name the 2 types of Encryption

Symmetric-the sender and receiver share the same private key, which they distribute to each other in a process called a key exchange. This key is used for both encrypting and decrypting data.
Asymmetric- two keys are used: one public and a second, private, key. The public key is used for encryption when sending a message (to a recipient) and private for decryption when the recipient receives the message.

How are private keys used to Encrypt?

If you want to prove that a message has been sent by you, you encrypt it with your private key; This allows anyone with your public key to decrypt it proving it is you that wrote the message. (This acts as a digital signature).

What is the process of hashing?

the process in which an input (called a key) is turned into a fixed size value (called a hash). This is achieved using algorithms called hash functions.