Sonu is not sure how exactly a digital signature system works. Help her to understand the process by choosing the most appropriate statement:-

A. A digital signature is formed subsequent to a message digest

B. A digital signature is formed by signing a message digest with a private key

C. A digital signature is formed by making a message interact with a one way hash function and signing it with 'a private key', the public key of which has been certified by a Certifying Authority

D. A digital signature is verified by using hash function and public key

Answer: Option D