iOS/Swift helper functions for storing text in Keychain

This is a collection of helper functions for saving text and data in the Keychain. As you probably noticed Apple's keychain API is a bit verbose. This library was designed to provide shorter syntax for accomplishing a simple task: reading/writing text values for specified keys. Tested in iOS 7 and 8.

What's Keychain?

Keychain is a secure storage on iOS device. You can store all kind of sensitive data in it: user passwords, credit card numbers, secret tokens etc. Once stored in Keychain this information is only available to your app, other apps can't see it. Besides that, iOS makes sure this information is kept and processed securely. For example, text stored in Keychain can not be extracted from iPhone backup or from its file system.

Setup

There are three ways you can add KeychainSwift to your Xcode project.

Add source (iOS 7+)

Simply add KeychainSwiftDistrib.swift file into your Xcode project.

Setup with Carthage (iOS 8+)

Alternatively, add github "exchangegroup/keychain-swift" ~> 3.0 to your Cartfile and run carthage update.

Setup with CocoaPods (iOS 8+)

If you are using CocoaPods add this text to your Podfile and run pod install.

use_frameworks!
pod 'KeychainSwift', '~> 3.0'

Setup in Swift 1.2 project

Use the previous version of the library.

Usage

Add import KeychainSwift to your source code if you used Carthage or CocoaPods setup methods.

let keychain = KeychainSwift()

keychain.set("hello world", forKey: "my key")

keychain.get("my key")

keychain.delete("my key")

keychain.clear() // delete everything from app's Keychain

In addition to strings one can set/get NSData objects.

let keychain = KeychainSwift()

keychain.set(nsDataObject, forKey: "my key")

keychain.getData("my key")

Advanced options

Keychain item access

Use withAccess parameter to specify the security level of the keychain storage. By default the .AccessibleWhenUnlocked option is used. It is one of the most restrictive options and provides good data protection.

KeychainSwift().set("Hello world", forKey: "key 1", withAccess: .AccessibleWhenUnlocked)

You can use .AccessibleAfterFirstUnlock if you need your app to access the keychain item while in the background. It may be needed for the Apple Watch apps. Note that it is less secure than the .AccessibleWhenUnlocked option.

See the list of all available access options.

Setting key prefix

One can pass a keyPrefix argument when initializing a KeychainSwift object. The string passed in keyPrefix argument will be used as a prefix to the keys supplied in set, get, getData and delete methods. I use the prefixed keychain in tests. This prevents the tests from changing the Keychain keys that are used when the app is launched manually.

Note that clear method still clears everything from the Keychain regardless of the prefix used.

let keychain = KeychainSwift(keyPrefix: "myTestKey_")

Demo app

Credits

The code is based on this example: https://gist.github.com/s-aska/e7ad24175fb7b04f78e7

License

Keychain Swift is released under the MIT License.

README.md 4.1 KB Riwayat Mentahan