Q12.What is a digital signature? What does its authentication mean? Giver various salient built-in features of a digital signature.

A digital signature is a cryptographic mechanism used to verify the authenticity and integrity of digital documents or messages. It ensures the origin and unaltered state of electronic communications, providing a secure and legally valid way to sign documents digitally.

Authentication by a digital signature means confirming the sender's identity and ensuring that the message has not been altered since it was signed. It provides assurance that the document truly originated from the claimed sender and remains untampered during transmission.

• Authenticity: Verifies the identity of the sender or signer, ensuring the message's origin and preventing impersonation.
• Integrity: Guarantees that the data has not been tampered with or altered during transmission, protecting against unauthorized modifications.
• Non-repudiation: Prevents the sender from falsely denying having sent the message or signed the document, providing legal enforceability.
• Security: Utilizes public-key cryptography, involving hashing and encryption, to secure the digital document and its associated data.