Compression, Encryption and Hashing

Question 1

Encryption

Answer 1

The process of encoding messages so it can be read only by sender and intended recipient

Question 2

What is the original data known as?

Answer 2

Plaintext

Question 3

What is the encrypted data known as?

Answer 3

Ciphertext

Question 4

What does symmetric encryption involve?

Answer 4

Using a single key to encrypt and decrypt data

Question 5

What does asymmetric encryption involve?

Answer 5

Using 2 keys (1 public, 1 private) to encrypt and decrypt data

Question 6

Types of compression

Answer 6

Lossy and lossless

Question 7

2 characteristics of lossy compression

Answer 7

• Some data is removed to reduce file size
• Compressed files can’t be reinstated to original detail

Question 8

2 characteristics of lossless compression

Answer 8

• Lossless retains all data by encoding it
• Original file can be regenerated

Question 9

Types of encoding`

Answer 9

• Dictionary
• Run-length

Question 10

Characteristic of dictionary encoding

Answer 10

Compression algorithm builds index where each item is recorded along with index reference

Question 11

Characteristic of run-length encoding

Answer 11

If data item is occurs multiple times than it’s stored once in index along with no. of reps

Question 12

Hashing

Answer 12

Method for creating random access to store data

Question 13

Hash function

Answer 13

Applied to field to calculate storage address for data associated with that item