Compare a digital signature with encryption. State what each is intended to provide and identify one property a signature alone does not establish.

### Why this is right The key distinction is purpose: a signature lets a recipient check origin and alteration, while encryption conceals content. The material also states that a signature alone does not prove freshness. ### The concept A digital signature uses a private key to sign and a corresponding public key to verify. The process uses a hash of the document, so a changed document should fail verification. Encryption is a separate operation that changes readable data into a form intended to prevent unauthorized reading. A document can be signed without being encrypted, encrypted without being signed, or both signed and encrypted. Freshness is another separate question: an old signed message may be replayed. ### What a good answer covers - Signing supports authenticity and integrity checks. - Encryption protects confidentiality by concealing content. - A signature is not encryption. - A signature alone does not prove freshness or prevent replay. ### Terms - **Authenticity**: Evidence that data is associated with its claimed source. - **Integrity**: Evidence that data has not been changed. - **Confidentiality**: Protection from unauthorized disclosure. - **Replay**: Re-sending a previously valid message. ### Remember Do not treat evidence of origin as evidence of secrecy or freshness.