# init(data:) Creates a nonce from the given data. ``` init(data: D) throws where D : DataProtocol ``` ## Parameters `data` A 12-byte data representation of the nonce. The initializer throws an error if the data isn’t 12 bytes long. ## Discussion Unless your use case calls for a nonce with a specific value, use the [`init()`](/documentation/CryptoKit/ChaChaPoly/Nonce/init()) method to instead create a random nonce. --- 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)