Message authentication refers to the process of verifying that a message has not been altered or tampered with during transmission. It’s not inherently outdated; however, certain methods of message authentication may become outdated due to advancements in technology or vulnerabilities being discovered. For example, older cryptographic algorithms or protocols may become vulnerable to attacks as computing power increases or new attack methods are developed. In such cases, its important to update to more secure authentication methods to ensure the integrity and security of transmitted messages.