---
title: "SecKeyDeriveFromPassword(_:_:_:)"
framework: security
role: symbol
role_heading: Function
path: "security/seckeyderivefrompassword(_:_:_:)"
---

# SecKeyDeriveFromPassword(_:_:_:)

Returns a key object in which the key data is derived from a password.

## Declaration

```swift
func SecKeyDeriveFromPassword(_ password: CFString, _ parameters: CFDictionary, _ error: UnsafeMutablePointer<Unmanaged<CFError>?>?) -> 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 doc://com.apple.documentation/documentation/CoreFoundation/CFError 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

Return Value The derived key object, or NULL on error. In Objective-C, call the CFRelease function to free the key’s memory when you are done with it.

## Discussion

Discussion The parameters dictionary must contain at least the following keys: kSecKeyKeyType—the type of symmetric key to generate. 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 - the algorithm to use for the pseudorandom-function. If zero, this defaults to kSecAttrPRFHmacAlgSHA1. For a list of possible values, see kSecAttrPRF Value Constants. 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—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.