Awesome

SwiftyKeychainKit

SwiftyKeychainKit is a simple Swift wrapper for Keychain Services API with the benefits of static typing. Define your keys in one place, use value types easily, and get extra safety and convenient compile-time checks for free.

Features

• Static typing and compile-time checks
• Support Gereric and Internet passwords
• Throwing and Result type get methods
• Easy way to implement support for custom types

Usage

Basic

let keychain = Keychain(service: "com.swifty.keychain")
let accessTokenKey = Keychain.Key<String>(key: "accessToken")

// Save or modify value
try? keychain.save("eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9", for : accessTokenKey)

// Get value 
let value = try keychain.get(accessTokenKey)

// Remove value 
try keychain.remove(accessTokenKey)

// Remove all values 
try keychain.removeAll()

Instantiation

// Generic password
let keychain = Keychain(service: "com.swifty.keychainkit")

// Internet password
let keychain = Keychain(server: URL(string: "https://www.google.com")!, protocolType: .https)

Define keys

For extra convenience, define your keys by extending KeychainKeys class and adding static properties:

extension KeychainKeys {
    static let username = Keychain.Key<String>(key: "username")
    static let age = Keychain.Key<Int>(key: "age")
}

and later in the code use shortcut dot syntax:

// save
try? keychain.save("John Snow", for: .username)

// get
let username = try keychain.get(.username)

Geting values

You can use subscripts and dynamicCallable syntax sugar to get value as Result<ValueType, KeychainError>

let username = try keychain[.username].get()

// or 

if case .success(let age) = keychain[.age] {
    ...
}

let username = try keychain(.username).get()

// or 

if case .success(let age) = keychain(.age) {
    ...
}

Both subscripts and dynamicCallable syntaxt available only for geting values. Currently Swift language limitation do not allow implement setter with error handling.

Default values

You can provide default value for get method and it will used than keychain key is nil and no error throw.

try keychain.get(.username, default: "Daenerys Targaryen")

// or

try keychain[.age, default: 18].get() 

SwiftUI

Basic

Use @AppKeychainStorage property wrapper for storing and reading values from Keychain, which will automatically reinvoke your view’s body property when the value changes.

• AppKeychainStorage property wrapper DOES NOT watches a key in KeyChain, and will not refresh your UI if that key changes. (Keychain on iOS lucking API to implement obsevation)
• AppKeychainStorage property wrapper DOES NOT implement "projected value" Binding. The main reason is Swift lucking feature to implement throwable 'set', ...

struct YourView: View {
    @AppKeychainStorage(.secret) var secret

    @State var secretInput: String = ""

    var body: some View {
        // Get value 
        switch secret {
            case .success(let value):
                if let value = value {
                    Text("Keychain value: \(value)")
                } else {
                    Text("Keychain missing value")
                }

            case .failure(let error):
                Text("Keychain error: \(error)")
        }

        // Set value
        TextField("Input secret", text: $secretInput)
        Button("Save") {
            do {
                try self._secret.set(secretInput)
            } catch {
                // process error
            }
        }

        // Remove value
         Button("Remove") {
            do {
                try self._secret.remove()
            } catch {
                // process error
            }
        }
    }
}

Configure Keychain

Besides the default keychain @AppKeychainStorage also supports any developer-defined Keychain.

struct YourView: View {
    @AppKeychainStorage(.secret, keychain: .accessGroupKeychain) var secret

    var body: some View {
        ...
    }
}

extension Keychain {
    // Keychain with custom access group to share Keychain item with extenstions
    static let accessGroupKeychain = Keychain(accessGroup: "NS8HLGG733.com.swifty.keychain.example")
}

Configure default Keychain

Using defaultAppKeychainStorage modifier allows setting a default Keychain for the view or scene, avoiding the need to set it repeatedly in each @AppKeychainStorage

@main
struct ExampleApp: App {
   var body: some Scene {
       WindowGroup {
           YourView()
               .defaultAppKeychainStorage(.accessGroupKeychain)
       }
       .defaultAppKeychainStorage(.accessGroupKeychain)
   }
}

Supported types

• Int
• String
• Double
• Float
• Bool
• Data

Codable

struct MyStruct: Codable, KeychainSerializable { ... }

NSCoding

class MyClass: NSObject, NSCoding, KeychainSerializable { ... }

Custom types

In order to save/get your own custom type that we don't support, you need to confirm it KeychainSerializable and implement KeychainBridge for this type.

As an example saving Array<String> using JSONSerialization:

extension Array: KeychainSerializable where Element == String  {
    public static var bridge: KeychainBridge<[String]> { return KeychainBridgeStringArray() }
}

class KeychainBridgeStringArray: KeychainBridge<[String]> {
    public override func set(_ value: [String], forKey key: String, in keychain: Keychain) throws {
        guard let data = try? JSONSerialization.data(withJSONObject: value, options: []) else {
            fatalError()
        }
        try? persist(value: data, key: key, keychain: keychain)
    }

    public override func get(key: String, from keychain: Keychain) throws -> [String]? {
        guard let data = try? find(key: key, keychain: keychain) else {
            return nil
        }

        return (try? JSONSerialization.jsonObject(with: data, options: [])) as? [String]
    }
}

Supported attributes

Common

• kSecAttrAccessGroup
• kSecAttrAccessible
• kSecAttrDescription
• kSecAttrComment
• kSecAttrCreator
• kSecAttrType
• kSecAttrLabel
• kSecAttrIsInvisible
• kSecAttrIsNegative
• kSecAttrAccount
• kSecAttrSynchronizable

Generic password

• kSecAttrAccessControl
• kSecAttrService
• kSecAttrGeneric

Internet password

• kSecAttrSecurityDomain
• kSecAttrServer
• kSecAttrProtocol
• kSecAttrAuthenticationType
• kSecAttrPort
• kSecAttrPath

Requirement

Swift version 5.0

Installation

let package = Package(
    dependencies: [
        .Package(url: "https://github.com/andriyslyusar/SwiftyKeychainKit.git", .exact("1.0.0-beta.2"))
    ]
)

Acknowledgement

• SwiftyUserDefaults - API design inspiration
• KeychainAccess - API wrapper knowledge source

Author

Andriy Slyusar

• https://twitter.com/andriyslyusar
• https://github.com/andriyslyusar

License

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