# update(data:) Incrementally updates the hash function with the given data. ``` mutating func update(data: D) where D : DataProtocol ``` ## Parameters `data` The next block of data for the ongoing digest calculation. You can provide this as any type that conforms to , like or an array of instances. ## Discussion Call this method one or more times to provide data to the hash function in blocks. After providing the last block of data, call the [`finalize()`](/documentation/CryptoKit/HashFunction/finalize()) method to get the computed digest. Don’t call the update method again after finalizing the hash function. --- 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)