ICT and digital signature – UGC NET Question

A digital signature uses asymmetric cryptography to bind a person's identity to a digital document through a unique key pair. Verification processes confirm that the document originated from the claimed sender and has not been altered in transit. In many countries, digital signatures have legal validity for e-governance and e-commerce transactions. Hence, the cryptographic authentication method described is a digital signature.

Option A:
Option A, digital watermark, embeds information into media for ownership identification but does not necessarily authenticate the sender in formal transactions.

Option B:
Option B is correct because ICT security frameworks explicitly define digital signatures as providing authenticity, integrity and non-repudiation, aligning with the functions listed in the stem.

Option C:
Option C, simple password, offers only basic authentication and does not involve cryptographic binding of identity to a specific document.

Option D:
Option D, captcha code, distinguishes human users from automated bots but does not certify document origin or integrity.