# authenticationCode(for:using:) Computes a message authentication code for the given data. ``` static func authenticationCode(for data: RawSpan, using key: SymmetricKey) -> HMAC.MAC ``` ## Parameters `data` The data for which to compute the authentication code. `key` The symmetric key used to secure the computation. ## Return Value The message authentication code. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)