Briefly explain the concept of digital signatures.

$[5$ Marks$]$

b$.$ Alice wants to establish a secure communication channel with Bob by digitally

signing her messages. Design a robust digital signature system tailored to

their communication needs. Provide detailed insights into the key

components, cryptographic algorithms, and security considerations.

i$.$ Identify and explain the key components required for the digital

signature system. What entities $($e$.$g$.,$ public keys, private keys,

certificates$)$ are essential for Alice and Bob to exchange secure

messages?