KeychainAccess

Apple products not only distinguish themselves for great design and UX, but also security. The Keychain and Touch ID are an example of that.

While great from a security point of view, the Keychain is not one of the developer’s best friends, with its C APIs and notoriously mysterious error messages.

KeychainAccess by Kishikawa Katsumi provides a much nicer set of Swift APIs that will make working with the Keychain a pleasure. And as a bouns there is also Touch ID and iCloud support.

How to read and write values to the Keychain

You can get an instance of the Keychain wrapper by using the Bundle Identifier of you application:

let keychain = Keychain(service: "com.theiostimes.keychainexample")

With this instance reading and writing data is very simple:

do {
    try keychain.set("1234-5678-90AB", key: "token")
} catch {
    // TODO: Handle write failure
}

do {
    let token = try keychain.get("token")
} catch {
    // TODO: Handle read failure
}

And there is support for subscript access as well, if you think that style makes your code more readable.

keychain["token"] = "1234-5678-90AB"
let _ = keychain["token"]

Note how with subscripting there is no need to try, in fact the values returned are optionals.

How to delete data from the Keychain

Removing data is as straightforward as writing it:

do {
    try keychain.remove("token")
    try keychain.removeAll()
} catch {
    // TODO: Handle delete failure
}

Configuring the Keychain

The Keychain interface can be configured in this neat chainable way:

Keychain(service: "com.theiostimes.keychainexample")
    .label("theiostimes.com (mokagio)")
    // Enable iCloud Sync
    .synchronizable(true)
    // Configure data availability
    .accessibility(.AfterFirstUnlock)

Next Steps

There is much more that can be done with KeychainAccess, and with the Keychain itself.

The very first place I would recommend you to visit if you want to find out more is Apple’s Keychain Services Concepts documentation. Once you’ll have a solid understanding of what can be done with the Keychain, head over to KeychainAccess’ project repo on GitHub and go through the README to learn more about the advanced features this library offers.

As usual all the code used in this tutorial is available on GitHub as well.

That’s it for today. See you tomorrow with a library to draw charts. Subscribe to the email list to avoid missing out.

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