Encryption Concepts

Question 1

describe what a hash is used for and how in 2 points, and give an example method

Answer 1

1) it is used to ensure data integrity
2) it uses a compression algorithm to reduce the data to a fixed length
3) MD5 and SHA are example algorithms

Question 2

Fill in the below features of Asymetric encryption:

1) it uses a ___ ___ and a ___ ___
2) it requires a ___ to issue certificates
3) either key can ___ or ____ the data

Answer 2

1) it uses a public key and a private key
2) it requires a PKI to issue certificates
3) either key can encrypt or decrypt the data

Question 3

Encryption normally includes an algorithm and a …

Answer 3

key

Question 4

What’s the difference between a stream cipher and a block cipher?

Answer 4

stream ciphers encrypt one bit at a time, block ciphers encrypt blocks of data at a time

Question 5

What name is given to the principle of validating an identity?

Answer 5

authentication

Question 6

If you encrypt the hash of an email message with the senders private key, what have you created?

Answer 6

a digital signature

Question 7

only the sender’s xxxx xxxx can decrypt the hash of an email

Answer 7

public key
Remember, they encrypt it with the private key. Anyone should be able to decrypt it to check the hash is correct. The recipient gets the public key from the sender’s public certificate.