UPSC Mains Answer: What is a digital signature? What does its authentication mean? Give various salient built-in features Of a digital signature. [100 words]

Difficulty Level: Medium

Pre-requisite: Basic understanding of cryptography, including symmetric and asymmetric encryption, public-key infrastructure (PKI), and the role of digital certificates in secure communication.

Sub-category: Science and Technology - Developments and their Applications

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A digital signature is a cryptographic mechanism that verifies the authenticity and integrity of digital messages or documents. It ensures the sender’s identity and confirms that the content has not been altered during transmission. Authentication of a digital signature means validating the sender’s identity using a public key, ensuring the signature is genuine and legally binding.
Salient built-in features include: 1. Authentication: Verifies the sender’s identity.
2. Integrity: Ensures the message remains unaltered.
3. Non-repudiation: Prevents the sender from denying their signature.
4. Encryption: Secures data using asymmetric cryptography (public and private keys).
5. Time-stamping: Records the exact time of signing for legal validity.