If that is indeed the case, than this definitely answers my question.
How can I verify the signatures and document's data integrity?
If the two are the same, he knows that the message was not tampered with, because only the sender has the private key, and there is no reasonable way to determine the private key from the public key. That's the Certificate Authority's job (CA for short).
The CA has it's own key pair - and it uses it's private key to sign a digital certificate for the key holder.
imports a public key and a signature that is alleged to be the signature of a specified data file and then verifies the authenticity of the signature.
The public key, signature, and data file names are specified on the command line.
In a PDF, most digital signatures are referred to as , because it’s used to identify the person signing it.
Trying to get a better grapple on how public/private keys work.
I am not able to understand that how the digital signature is verified.
I know that digital signature will be attached to the message and sent by sender to receiver.
When you receive a signed document, you may want to validate its signature(s) to verify the signer and the signed content.