Question

"Asymmetric Crypto System" under Information Technology Act means a system of a secure key pair consisting of a private key for creating a digital signature and

• A. an individual key to verify the digital signature
• B. a lock to verify the digital signature
• C. a public key to verify the digital signature
• D. a Government key to verify the digital signature

Hint:

Remember the basic principle of digital signatures under the IT Act: \textbf{Private Key Signs, Public Key Verifies}. This simple rule will help you answer any question on the mechanics of asymmetric crypto systems.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The question asks for the definition of an "asymmetric crypto system" as defined in the Information Technology Act, 2000. This is the technological foundation for digital signatures.
Step 2: Key Formula or Approach:
Section 2(1)(f) of the Information Technology Act, 2000 defines "asymmetric crypto system" as "a system of a secure key pair consisting of a private key for creating a digital signature and a public key to verify the digital signature."
Step 3: Detailed Explanation:
An asymmetric crypto system, also known as public-key cryptography, uses two related keys:
1. Private Key: This key is kept secret by the owner. It is used to create the digital signature (i.e., to sign a document electronically).
2. Public Key: This key is made publicly available. It is used to verify a digital signature created by the corresponding private key.
The system is "asymmetric" because the key used for signing (private) is different from the key used for verification (public). The definition in the Act perfectly reflects this mechanism. Option (C) is a direct and accurate completion of the statutory definition.
Step 4: Final Answer:
The system consists of a private key for creating a digital signature and a public key to verify the digital signature.

Answer 2

The question is testing the statutory definition of an "asymmetric crypto system" and specifically what completes the definition after "a private key for creating a digital signature and". Let's examine each option.

1. an individual key to verify the digital signature: "Individual key" is not a recognised term in this definition or in cryptography generally, an asymmetric system is built around a specific pair, a private key and a public key, not a vaguely described "individual" key.
2. a lock to verify the digital signature: A "lock" is not a cryptographic term used in digital signature verification at all, this option is simply not a real concept in this context.
3. a public key to verify the digital signature: This is correct. In an asymmetric (public key) system, the signer keeps a private key secret to create the signature, and anyone can use the corresponding public key, which is openly shared, to confirm that the signature was genuinely created using that private key. This pairing, private key to sign, public key to verify, is the defining feature of the system.
4. a Government key to verify the digital signature: There is no such thing as a "Government key" in the statutory definition of an asymmetric crypto system. Certifying authorities may be regulated by government bodies, but verification itself uses the public key of the signer, not any government issued key.

Since an asymmetric system by definition pairs a private signing key with a public verifying key, and none of the other terms describe a real element of this mechanism, the description is completed correctly only by the public key option.

Therefore, the correct answer is a public key to verify the digital signature.