To test the digital signature, the verifier will use sender's public key.

• A. True
• B. False
• C. Not sure
• D. It depends

Answer: (B)

In digital signatures, the signer uses a private key to create a signature on the message (usually by signing a hash of the message). The verifier then uses the corresponding public key to check that signature. The verification process essentially confirms that the signature was produced with the private key that matches the public key, without revealing the private key itself. In practice, the verifier obtains the sender’s public key through a trusted certificate to ensure it actually belongs to the sender; if the public key isn’t trusted or has been tampered with, verification cannot be reliably trusted. So the verification step relies on the sender’s public key to validate the signature.