Public Key Cryptography

Question 1

What are the two properties needed for a public key signature scheme?

Answer 1

Correctness
Unforgeability

Question 2

How does a client verify the authenticity of a certificate it has received from a server?

Answer 2

That certificate will be signed by a certifying authority, the client requests the CA’s certificate and verifies the server’s certificate. It verifies the signature of every certificate until it reaches a root certificate that the client has saved.

Question 3

What 3 algorithms makes up a key encapsulation mechanism?

Answer 3

Key generation
Encapsulation - takes in a public key and generates a ciphertext and a session key
Decapsulation - takes in a private key and a ciphertext and returns the session key

Question 4

What is a hybrid encryption scheme?

Answer 4

Uses a key encapsulation mechanism to share a symmetric encryption key which the message is encrypted using.