A digital signature uses asymmetric encryption to create a unique hash of the message which can be validated by the recipient to verify that the message has not been tampered with during transmission. This ensures the integrity of the message. A MAC (Message Authentication Code) ensures the message comes from a known sender, and non-repudiation prevents denial of an action such as sending a message, but neither specifically addresses the message content being altered. Encryption protects the confidentiality of the message, not necessarily the integrity.