SSL Certificate - What is the use of the private key in a root certificate?

Question

I am new to Cryptogrphy, HTTPS and SSL !!! If i am not wrong , the private key of an End Entity certificate (certificate issued by trusted CA like Verisign) is used to decrypt the information sent by the client ! But does a root certificate also have a Private Key?

If Yes, then I wanted to know where exactly the private key of a root certificate is used? What happens if it is leaked ?

Answer 1

If I am not wrong, the private key of an End Entity certificate (certificate issued by trusted CA like Verisign) is used to decrypt the information sent by the client

You are wrong. It isn't. The peer's own private key is used to sign the certificate so the client can verify that the peer owns the certificate he presents, and the private key of signing certificates is used to, err, sign certificates.

Answer 2

The root certificate's private key is (normally) only used to sign the intermediate certificates. Compromising it allows you to create new intermediate certificates, and by extension, certificates for any domain.

Answer 3

A root certificate is the top-most certificate of the tree, the private key of which is used to "sign" other certificates. All certificates immediately below the root certificate inherit the trustworthiness of the root certificate - a signature by a root certificate is somewhat analogous to "notarizing" an identity in the physical world. If you knew the private key, you could create new (counterfeit) certificates.