# SecKeyCreateEncryptedData(_:_:_:_:) Encrypts a block of data using a public key and specified algorithm. ``` func SecKeyCreateEncryptedData(_ key: SecKey, _ algorithm: SecKeyAlgorithm, _ plaintext: CFData, _ error: UnsafeMutablePointer?>?) -> CFData? ``` ## Parameters `key` The public key to use to perform the encryption. `algorithm` The encryption algorithm to use. Use one of the encryption algorithms listed in [`SecKeyAlgorithm`](/documentation/Security/SecKeyAlgorithm). You can use the [`SecKeyIsAlgorithmSupported(_:_:_:)`](/documentation/Security/SecKeyIsAlgorithmSupported(_:_:_:)) function to test that the key is suitable for the algorithm. `plaintext` The data to be encrypted. `error` The address of a object. If an error occurs, this is set to point at an error instance that describes the failure. ## Return Value The encrypted data or `NULL` on failure. In Objective-C, call the function to free the data’s memory when you are done with it. ## Discussion You can decrypt this data with the corresponding private key and a call to [`SecKeyCreateDecryptedData(_:_:_:_:)`](/documentation/Security/SecKeyCreateDecryptedData(_:_:_:_:)). --- 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)