What does a digital signature, as described in the course material, provide evidence about?

### Why this is right A signature is used to check whether the document is associated with the signer and whether its contents have changed since signing. Those properties are authenticity and integrity. ### The concept **Authenticity** concerns whether data is associated with the claimed sender. **Integrity** concerns whether the data has been altered. A signature can support checks of both properties, but it does not hide the data. It also does not, by itself, prove that a signed message is new; an old valid message could be replayed. ### The other options - **A. The document's confidentiality and storage location**: confidentiality means preventing unauthorized reading; a signature does not conceal content or establish where a file is stored. - **C. The message's freshness and secrecy**: a signature does not prove freshness, and secrecy requires a separate protective mechanism. - **D. The identity of every person who has read the document**: a signature does not track readers. ### Terms - **Authenticity**: Evidence that data came from the claimed source. - **Integrity**: The condition of data remaining unchanged. - **Confidentiality**: Protection against unauthorized disclosure. - **Replay**: Re-sending a previously valid message. ### Remember A signature helps check origin and alteration, not secrecy or freshness.