The statement 'The verifier uses the sender's public key to test the digital signature' is true.

• A. True
• B. False
• C. Not Determinable
• D. Depends

Answer: (B)

In digital signatures, authenticity and integrity are proven by using the signer’s public key during verification. The signer creates a signature with their private key over the message (typically a hash of the message). Anyone who has the signer’s public key can run the verification operation on the signature and the message; if it checks out, it confirms that the signature was created with the corresponding private key and that the message has not been altered. Because verification rests on the public key belonging to the claimed sender (and this key must be trusted via a certificate or trusted store), the statement that the verifier uses the sender’s public key to test the digital signature is true.