Explanation:

A digital signature is a mathematical technique used to validate the authenticity and integrity of a message, software or digital document. As the digital equivalent of a handwritten signature or stamped seal, a digital signature offers far more inherent security, and it is intended to solve the problem of tampering and impersonation in digital communications.

• Digital Signatures provide Authentication, Privacy, Non repudiation and Integrity in the virtual world. IT Act 2000 in India gives legal validity to electronic transactions that are digitally signed. Therefore we need digital signatures for secure messaging, online banking applications, online workflow applications, e-tendering, supply chain management etc.
• Digital Certificates are digital documents attesting to the binding of a public key to an individual or specific entity. They allow verification of the claim that a specific public key does in fact belong to a specific individual. Digital Certificates help prevent someone from using a phony key to impersonate someone else.