# SecKeyUnwrapSymmetric(_:_:_:_:) Unwraps a wrapped symmetric key. ``` func SecKeyUnwrapSymmetric(_ keyToUnwrap: UnsafeMutablePointer?>, _ unwrappingKey: SecKey, _ parameters: CFDictionary, _ error: UnsafeMutablePointer?>?) -> SecKey? ``` ## Parameters `keyToUnwrap` The wrapped key to unwrap. `unwrappingKey` The key that must be used to unwrap `keyToUnwrap`. `parameters` A parameter list for the unwrapping process. This is usually either an empty dictionary or a dictionary containing a value for [`kSecAttrSalt`](/documentation/Security/kSecAttrSalt). `error` A pointer to a variable where an error object is stored upon failure. If not `NULL`, the caller is responsible for checking this variable and releasing the resulting object if it exists. ## Return Value The unwrapped key, or `NULL` on failure. In Objective-C, call the function to free the key’s memory when you are done with it. --- 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)