Asymmetric Encryption Introduction

Question 1

Explain how a hash function works…

Answer 1

A hash function gives a unique, fixed output given an input. The output is called a digest or hash value.

Question 2

What are the 2 main desirable properties of hash functions?

Answer 2

• Irreversible
• Collision resistant

Question 3

What does it mean for a hash function to be collision resistant? Explain how this might be implemented…

Answer 3

Collision resistant means that a hash function will never output a value that is already stored in the database.

One way of ensuring this is to assign a unique number (salt) to each hash value in the database. The salt operates on has value to ensure uniqueness and avoid collision resistant.

Question 4

Give a real life example of the use of hash functions…

Answer 4

Passwords - A login portal will need to use hashing to create a digest from the input password. This password is hashed, and the digest is stored in the database containing all user details. Salting is used to ensure that even if multiple users use the same password, the hashed value stored for their password will always be unique.

Question 5

In what 2 fields has asymmetric encryption made advances in?

Answer 5

Message authentication and key distribution.

Question 6

What type of functions are used for Asymmetric encryption?

Answer 6

Purely mathematical functions.

Question 7

What are the 2 main misconceptions of Asymmetric Encryption? Why are they false?

Answer 7

More secure - Not true, security mostly relies on the key strength. DES is still yet to be broken despite being symmetric encryption. Therefore, using either is secure.
Making symmetric obsolete - Not true, symmetric is faster and less computationally costly. Therefore, asymmetric is being used for symmetric key exchanges and message authentication more and more.