Hash Chain Question (Answer both parts):

Hash chains: a) Alice and Bob are securely communicating via a secret key encryption scheme. Currently, Alice has to generate a sccret key sk# and scnd it to Bob, before scnding cach ciphertext C# This is costly as each time the key sk# is sent is has to be encrypted at Alice's side and decrypted on Bob's side. Explain how we can use hash chains to solve this problem b) There are a number of trade-offs in using hash chains (in general, NOT only concerning the above case), explain TWO advantages and TWO disadvantages of using hash chains. Hash chains: a) Alice and Bob are securely communicating via a secret key encryption scheme. Currently, Alice has to generate a sccret key sk# and scnd it to Bob, before scnding cach ciphertext C# This is costly as each time the key sk# is sent is has to be encrypted at Alice's side and decrypted on Bob's side. Explain how we can use hash chains to solve this problem b) There are a number of trade-offs in using hash chains (in general, NOT only concerning the above case), explain TWO advantages and TWO disadvantages of using hash chains