# SecKeyDeriveFromPassword(_:_:_:) Returns a key object in which the key data is derived from a password. ``` func SecKeyDeriveFromPassword(_ password: CFString, _ parameters: CFDictionary, _ error: UnsafeMutablePointer?>?) -> SecKey? ``` ## Parameters `password` The password from which the key should be derived. `parameters` A set of parameters for deriving the password. `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 derived key object, or `NULL` on error. In Objective-C, call the function to free the key’s memory when you are done with it. ## Discussion The parameters dictionary must contain at least the following keys: - [`kSecKeyKeyType`](/documentation/Security/kSecKeyKeyType)—the type of symmetric key to generate. - [`kSecAttrSalt`](/documentation/Security/kSecAttrSalt)—a `CFDataRef` object containing the salt value that is mixed into the pseudorandom rounds. The parameters dictionary may contain the following optional keys: - [`kSecAttrPRF`](/documentation/Security/kSecAttrPRF) - the algorithm to use for the pseudorandom-function. If zero, this defaults to [`kSecAttrPRFHmacAlgSHA1`](/documentation/Security/kSecAttrPRFHmacAlgSHA1). For a list of possible values, see `kSecAttrPRF Value Constants`. - [`kSecAttrRounds`](/documentation/Security/kSecAttrRounds)—the number of times to call the pseudorandom function. If zero, the count is computed so that computation will take 1/10 of a second (on average). - [`kSecAttrKeySizeInBits`](/documentation/Security/kSecAttrKeySizeInBits)—a `CFNumberRef` value containing the requested key size in bits. The key size must be valid for the key type. Defaults to 128 if not provided. --- 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)