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Valet

Valet lets you securely store data in the iOS or OS X Keychain without knowing a thing about how the Keychain works. It’s easy. We promise.

Getting Started

To install Valet in your iOS or OS X project, install with CocoaPods

on iOS:

platform :ios, '6.0'
pod 'Valet'

on OS X:

platform :osx, '10.10'
pod 'Valet'

Or manually checkout the submodule with git submodule add [email protected]:Square/Valet.git, drag Valet.xcodeproj to your project, and add Valet as a build dependency.

Usage

Basic Initialization

VALValet *myValet = [[VALValet alloc] initWithIdentifier:@"Druidia" accessibility:VALAccessibilityWhenUnlocked];

To begin storing data securely using Valet, you need to create a VALValet instance with:

  • An identifier – a string that is used to identify this Valet.
  • An accessibility value – an enum (VALAccessibility) that defines when you will be able to store and retrieve data.

This instance can be used to store and retrieve data securely, but only when the device is unlocked.

Choosing the Best Accessibility Value

The VALAccessibility enum is used to determine when your secrets can be accessed. It’s a good idea to use the strictest accessibility possible that will allow your app to function. For example, if your app does not run in the background you will want to ensure the secrets can only be read when the phone is unlocked by using VALAccessibilityWhenUnlocked or VALAccessibilityWhenUnlockedThisDeviceOnly.

Reading and Writing

NSString *const username = @"Skroob";
[myValet setString:@"12345" forKey:username];
NSString *const myLuggageCombination = [myValet stringForKey:username];

Valet’s API for securely reading and writing data is similar to that of an NSMapTable; use -setObject:forKey: and -setString:forKey: to write objects and -objectForKey: and -stringForKey: to read objects. Valets created with a different class type, via a different initializer, or with a different identifier or accessibility attribute will not be able to read or modify values in myValet.

Sharing Secrets Among Multiple Applications

VALValet *mySharedValet = [[VALValet alloc] initWithSharedAccessGroupIdentifier:@"Druidia" accessibility:VALAccessibilityWhenUnlocked];

This instance can be used to store and retrieve data securely across any app writen by the same developer with the value Druidia under the keychain-access-groups key in the app’s Entitlements file, when the device is unlocked. myValet and mySharedValet can not read or modify one another’s values because the two Valets were created with different initializers. You can use the -initWithSharedAccessGroupIdentifier:accessibility: initializer on any Valet class to allow for sharing secrets across applications written by the same developer.

Sharing Secrets Across Devices with iCloud

VALSynchronizableValet *mySynchronizableValet = [[VALSynchronizableValet alloc] initWithIdentifier:@"Druidia" accessibility:VALAccessibilityWhenUnlocked];

This instance can be used to store and retrieve data that can be retrieved by this app on other devices logged into the same iCloud account with iCloud Keychain enabled. mySynchronizableValet can not read or modify values in myValet or mySharedValet because mySynchronizableValet is of a different class type. If iCloud Keychain is not enabled on this device, secrets can still be read and written, but will not sync to other devices.

Protecting Secrets with Touch ID or iOS Passcode

VALSecureEnclaveValet *mySecureEnclaveValet = [[VALSecureEnclaveValet alloc] initWithIdentifier:@"Druidia"];

This instance can be used to store and retrieve data in the Secure Enclave (supported on iOS 8.0 or later). Reading or modifying items in this Valet will require the user to confirm their presence via Touch ID or by entering their iOS passcode. If no passcode is set on the device, this instance will be unable to access or store data. Data is removed from the Secure Enclave when the user removes a passcode from the device. Storing data using VALSecureEnclaveValet is the most secure way to store data on iOS.

Migrating Existing Keychain Values into Valet

Already using the Keychain and no longer want to maintain your own Keychain code? We feel you. That’s why we wrote -migrateObjectsMatchingQuery:removeOnCompletion:. This method allows you to migrate all your existing Keychain entries to a Valet instance in one line. Just pass in an NSDictionary with the kSecClass, kSecAttrService, and any other kSecAttr* attributes you use – we’ll migrate the data for you.

Debugging

Valet guarantees it will never fail to write to or read from the keychain unless canAccessKeychain returns NO. There are only a few cases that can lead to the keychain being inaccessible:

  1. Using the wrong VALAccessibility for your use case. Examples of improper use include using VALAccessibilityWhenPasscodeSetThisDeviceOnly when there is no passcode set on the device, or using VALAccessibilityWhenUnlocked when running in the background.
  2. Initializing a Valet with initWithSharedAccessGroupIdentifier: when the shared access group identifier is not in your entitlements file.
  3. Using VALSecureEnclaveValet on an iOS device that doesn't have a Secure Enclave. The Secure Enclave was introduced with the A7 chip, which first appeared in the iPhone 5S, iPad Air, and iPad Mini 2.
  4. Running your app in DEBUG from Xcode. Xcode sometimes does not properly sign your app, which causes a failure to access keychain due to entitlements. If you run into this issue, just hit Run in Xcode again. This signing issue will not occur in properly signed (not DEBUG) builds.

Contributing

We’re glad you’re interested in Valet, and we’d love to see where you take it.

Any contributors to the master Valet repository must sign the Individual Contributor License Agreement (CLA). It’s a short form that covers our bases and makes sure you’re eligible to contribute.

When you have a change you’d like to see in the master repository, send a pull request. Before we merge your request, we’ll make sure you’re in the list of people who have signed a CLA.

Thanks, and please do take it for a joyride!