I am not able to understand that how the digital signature is verified.
:) The pivotal part is that their is a pair of keys that were generated together. So giving you my public key, along with the encrypted data and signature as described is just about as trustworthy as giving you a business card that I had printed at Staples for $50.
Next, to deal with a digital signature, the sender sends: The verifier performs the Decrypt operation above and compares his output with the original data. To really trust that I am who I say I am, and am therefore trust worthy, you need someone to sign off on my identity (like checking a driver's license).
then receiver uses the public key is used to verify it.
Here are my questions: A public key is part of a two key pair used in assymetric cryptography.
For highly secure systems, additional checks of up to the minute status information can be performed.