KeyStorage

KeyStorage is a simple secure key persistance library written in Swift. Persist passwords, preferences, and other key information quickly, easily and securely using the Keychain or NSUserDefaults.

Features

• Strongly typed persistance to either KeyChain or NSUserDefaults
• Built-in AES 256 encryption [feature in process]
• Extensible - add new storage or encrytion providers
• Keychain helpers for finding AccessGroup information

Requirements

• Xcode 8.2 or newer
• Swift 3.0

Installation

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

pod "KeyStorage"

Usage

There are five main classes in KeyStorage:

1. KeyStorage - The protocol which all of the storage providers must conform
2. KeyStorageCrypter - The protocol used to encrypt and decrypt key values
3. KeyStorageKeyChainProvider - A keychain implementation of the KeyStorage protocol
4. KeyStoreDefaultsProvider - A NSUserDefaults implementation of the KeyStorage protocol
5. KeychainHelpers - Tools for workign with the iOS keychain

Save Options

Each of the KeyStorage providers has a variety of type safe options to save key information. Please visit the wiki for more details.

Return Options

Each of the KeyStorage providers has a variety of type safe options to read key information. Please visit the wiki for more details.

Actions / Helpers

KeyStorage provides a few methods to help you work with your StorageProvders.

exists - Returns a Boolean if the specified key exists

let doesExist = keyStoreProvider.exists(forKey: "Hello")

removeKey - Removes the stored value for the specified key

let success = keyStoreProvider.removeKey(forKey: "Hello")
print("was success? \(success)")

removeAllKeys - Removes all stored values for the KeyStorage provider

let success = keyStoreProvider.removeAllKeys()
print("was success? \(success)")

Storage Providers

KeyStoreDefaultsProvider

The KeyStoreDefaultsProvider storage provider manages persistance to NSUserDefaults.

KeyStoreDefaultsProvider - Creation

The KeyStoreDefaultsProvider can be created with the following optional arguments.

suiteName : String

The specified app group name that will be used

let provider = KeyStoreDefaultsProvider(suiteName: "MyAppGroup")

cryptoProvider : KeyStorageCrypter

The encryption provider that will be used to encrypt and decrypt key values

let provider = KeyStoreDefaultsProvider(cryptoProvider: myCryptoProvider)

Combined Example

You can specify both if you wish to use an encryption provider and implement app group sharing.

let provider = KeyStoreDefaultsProvider(suiteName: "MyAppGroup", cryptoProvider: myCryptoProvider)

KeyStorageKeyChainProvider

The KeyStorageKeyChainProvider storage provider manages persistance to iOS Keychain.

KeyStorageKeyChainProvider - Creation

The KeyStorageKeyChainProvider can be created with the following optional arguments.

serviceName : String

The serviceName used to identify key values stored in the Keychain.

let provider = KeyStorageKeyChainProvider(serviceName: "myApp")

accessGroup : String

The Keychain Access Group used to identify key values stored in the Keychain. This must be implemented if you are using Keychain sharing.

let provider = KeyStorageKeyChainProvider(accessGroup: "myApp")

cryptoProvider : KeyStorageCrypter

The encryption provider that will be used to encrypt and decrypt key values

let provider = KeyStorageKeyChainProvider(cryptoProvider: myCryptoProvider)

accessible : KeyChainInfo.accessibleOption

The accessibility level of the values in the Keychain. See the Keychain documentation here for details.

let provider = KeyStorageKeyChainProvider(accessible: .afterFirstUnlock)

Combined Example

You can combine all of the above as needed. Below is an example of this fully implemented.

let provider = KeyStorageKeyChainProvider(serviceName: "myApp", accessGroup: "my-awesome-group", accessible: .afterFirstUnlockThisDeviceOnly, cryptoProvider: myCryptoProvider)

KeychainHelpers

Get Keychain AccessGroup Information

Programmatically look-up your application’s App ID Prefix and default Keychain Group.

//Get Information 
let info = KeychainHelpers.getAccessGroupInfo()

print("App ID Prefix \(info.prefix)")
print("KeyChain Group \(info.keyChainGroup)")
print("Raw kSecAttrAccessGroup value \(info.rawValue)")

Author

Ben Bahrenburg, @bencoding

License

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