compression, encryption and hashing

Question 1

what is compression

Answer 1

reducing storage space required of a file
important for sharing files over networks

Question 2

lossy compression

Answer 2

reduces file size while removing some information

Question 3

lossless compresion

Answer 3

reduces file size and doesnt lose any information
og file can be recovered

Question 4

what is run length encoding

Answer 4

method of lossless compression
repeated values are removed and replaces with one occurence of the data and then how many imes it should be repeated

Question 5

what is dictionary encoding

Answer 5

method of lossless compression
frequently occuring pieces of data are replaced with an index and stored in a dictionary

Question 6

what is symmetric encryption

Answer 6

sender and reciever share the same private key in a key exchange

Question 7

what is asymmetric encryption

Answer 7

Asymmetric encryption uses two keys: a public key, which is shared with everyone, and a private key, which you keep secret. If someone wants to send you a secure message, they use your public key to encrypt it, and only you can decrypt it with your private key.
To prove a message is really from you, you can encrypt it with your private key. Since anyone can access your public key, they can use it to check that the message came from you.