Keychain

Keychain is an easy-to-use wrapper class for using the system keychain and offers a simple interface to store user credentials with more advance features available.

Features

• Quick methods for saving to, loading and deleting from the keychain.
• Basic save, load and delete methods allowing for advanced query/attributes dictionaries.
• Keychain also includes the KeychainItem class, that allows for saving and loading items from the keychain as instances of the class, making it even easier to use the system keychain. (See below for more information).

Requirements

• iOS 8

Installation

Keychain is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "Keychain"

For Swift 3 support, use the following:

pod "Keychain", :git => 'https://github.com/pkrll/Keychain.git', :branch => 'swift3'

Quick usage

There are several ways to go about to save an item to the keychain. The most basic is just calling the class function save(_:forKey:). This will save the specified value to the keychain, that can later be retrieved by using the value passed to the forKey parameter.

// To save some value to the keychain use:
Keychain.save("some value", forKey: "Some key")

// You can retrieve it by using the same key:
let data = Keychain.load("Some Key")
print(data)
// Prints "some value"

Deleting the item from the keychain follows the same logic:

if Keychain.delete("Some Key") {
    // Success!
}

Advanced usage

If you need to create custom attribute dictionaries (for example, for setting the service and/or account attributes yourself instead of letting the wrapper handle it), Keychain also allows for more advanced operations.

(Note: The advande save/load/delete methods require you to create the attribute/search dictionaries. Please consult the Keychain Service Reference for more information.)

Save Example (advanced)

The advanced save(_:) function returns a tuple with two members: (success: Bool, statusCode: OSStatus).

let value = "Some value"

let attributes: [String: AnyObject] = [
  kSecClass as String       : kSecClassGenericPassword as String,
  kSecAttrAccount as String : "Some Account",
  kSecAttrService as String : "Some Service",
  kSecValueData as String   : value.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)!
]

let result = Keychain.save(attributes)

if result.success {
  // Success!
} else {
  // Failure!
  // Check OSStatus
  print(result.statusCode)
}

Load Example (advanced)

The advanced load(_:) function will return a tuple with three members: (success: Bool, data: NSData?, statusCode: OSStatus).

let query: [String: AnyObject] = [
  kSecClass as String       : kSecClassGenericPassword as String,
  kSecMatchLimit as String  : kSecMatchLimitOne,
  kSecReturnData as String  : kCFBooleanTrue,
  kSecAttrService as String : "Some Service",
  kSecAttrAccount as String : "Some Account"
]

let result = Keychain.load(query)

if result.success {
  let string = String(data: result.data as! NSData, encoding: NSUTF8StringEncoding)
  print(string) // Prints "Some value"
} else {
  print(result.statusCode)
  }

Delete Example (Advanced)

The advanced delete(_:) function returns a tuple with two members: (success: Bool, statusCode: OSStatus).

let query: [String: AnyObject] = [
  kSecClass as String       : kSecClassGenericPassword as String,
  kSecAttrService as String : "Some Service",
  kSecAttrAccount as String : "Some Account"
]

let result = Keychain.delete(query)

if result.success {
  print(result.success)
} else {
  print(result.statusCode)
}

Using KeychainItem (Beta)

Keychain includes the class KeychainItem that hides away a lot of the ugliness that you'd otherwise have to handle when working with Keychain Services.

Instead of definining attributes and search dictionaries, KeychainItem offers a more intuitive, OOP-way of using Keychain Services.

(Note: The KeychainItem class is still in development, and works best/only with items of classes kSecClassGenericPassword and kSecClassInternetPassword).

Save Example (KeychainItem)

let kItem = KeychainItem(withItemClass: KeychainItemClass.GenericPassword)
kItem.account = "pkrll"
kItem.service = "github.com"
kItem.label = "Github"
kItem.value = "somePassword"
kItem.synchronizable = true

if kItem.save() {
  // Success!
} else {
  // Failure!!
  let statusCode = kItem.OSStatusCode
  print(statusCode)
}

Load Example (KeychainItem)

The below code shows how to load items as instances of KeychanItem as of today. (In future releases it should however be possible to load a single item by creating an instance of KeychainItem, instead of creating a search dictionary).

let query: [String: AnyObject] = [
  kSecClass as String                 : KeychainItemClass.GenericPassword.rawValue as String,
  kSecMatchLimit as String            : kSecMatchLimitAll,
  kSecMatchCaseInsensitive as String  : kCFBooleanTrue,
  kSecReturnData as String            : kCFBooleanTrue,
  kSecReturnAttributes as String      : kCFBooleanTrue,
  kSecAttrSynchronizable as String    : kSecAttrSynchronizableAny
]

let items = KeychainItemFactory.load(query)
// Returns an array of KeychainItem objects ( [KeychainItem] )

Update Example (KeychainItem)

Use the update(_:) method to update the keychain item.

kItem.value = "A new value"

if kItem.update() {
  // Success
} else {
  print(kItem.OSStatusCode)
}

Author

Ardalan Samimi, ardalan@saturnfive.se

License

Keychain is available under the MIT license. See the LICENSE file for more info.