Which of the following is not a primary and direct characteristic of a digital signature?

Correct option is C

A digital signature is primarily used to ensure integrity, authenticity, and non-repudiation of a digital message or document. It verifies that the message has not been altered (integrity), confirms the identity of the sender (authenticity), and prevents the sender from denying having sent the message (non-repudiation). However, confidentiality—keeping the content secret—is not a direct function of a digital signature. Confidentiality is achieved through encryption, not through signing alone.
Important Key Points:
1. Integrity: Ensures that the data has not been modified after it was signed.
2. Authenticity: Confirms that the message was sent by a verified sender using their private key.
3. Non-repudiation: Prevents the sender from denying their involvement in sending the message.
4. How Digital Signatures Work? They use asymmetric cryptography (private key for signing, public key for verification).
5. Where Digital Signatures Are Used? Secure emails, software distribution, online banking, legal documents, and e-governance.
6. Separation of Roles: Digital signatures ≠ Encryption; they serve different security objectives.
Knowledge Booster:
· Why option (a) Integrity is not the answer? Integrity is a core and direct feature of digital signatures.
· Why option (b) Authenticity is not the answer? Digital signatures explicitly verify the identity of the sender.
· Why option (d) Non-repudiation is not the answer? Digital signatures provide legal proof that the sender cannot deny the action.
· To achieve confidentiality + integrity + authenticity, systems typically use encryption along with digital signatures.