SwiftKeychain

Swift wrapper for working with the Keychain API implemented with protocol oriented programming.

Abstract

You create an implementation of the KeychainGenericPasswordType protocol that encapsulates the data that you want to store in the Keychain. Most of the implementation is done for you by using default protocol implementations, such as setting the default service name and access mode (kSecAttrAccessibleWhenUnlocked).

Then you call the KeychainItemType methods to save, remove or fetch the item from the provided as argument KeychainServiceType protocol implementation.

Let's say we want to store the access token and username for an Instagram account in the Keychain:

struct InstagramAccount: KeychainGenericPasswordType {
    let accountName: String
    let token: String
    var data = KeychainData()
    
    var dataToStore: KeychainData {
        return ["token": token]
    }
    
    var accessToken: String? {
        return data["token"] as? String
    }
    
    init(name: String, accessToken: String = "") {
        accountName = name
        token = accessToken
    }
}

In var dataToStore: KeychainData you return the Dictionary (KeychainData is just an alias for [String: any Sendable]) that you want to be saved in the Keychain and when you fetch the item from the Keychain its data will be populated in your var data: KeychainData property.

Save Item

let newAccount = InstagramAccount(name: "John", accessToken: "123456")

do {
    try newAccount.saveInKeychain()
} catch {
    print(error)
}

Note

The provided implementation of the KeychainServiceType protocol will replace the item if it already exists in the Keychain database.

Remove Item

let account = InstagramAccount(name: "John")

do {
    try account.removeFromKeychain()
} catch {
    print(error)
}

Fetch Item

var account = InstagramAccount(name: "John")

do {
    try account.fetchFromKeychain()
    
    if let token = account.accessToken {
        print("name: \(account.accountName), token: \(token)")
    }
} catch {
    print(error)
}

Support for classes

By default, stored data supports only value types such as strings and numbers. If you want to store objects of any class (for example, NSDate) in the Keychain, you need to implement the storedClasses property of the KeychainItemType protocol. In this property, you must explicitly list all the class types that will be stored:

struct InstagramAccount: KeychainGenericPasswordType {
    let accountName: String
    let token: String
    let tokenDate: NSDate
    var data = KeychainData()
    
    var dataToStore: KeychainData {
        return [
            "token": token,
            "tokenDate": tokenDate
        ]
    }
        
    var storedClasses: [AnyClass] {
        return [NSDate.self]
    }
    
    var accessToken: String? {
        return data["token"] as? String
    }

    var accessTokenDate: NSDate? {
        return data["tokenDate"] as? NSDate
    }
    
    init(name: String, accessToken: String, accessTokenDate: NSDate) {
        accountName = name
        token = accessToken
        tokenDate = accessTokenDate
    }
}

Installation

SwiftKeychain package requires Swift 5.5 and supports macOS, iOS, watchOS, tvOS and visionOS.

Install

.package(url: "https://github.com/slidoapp/SwiftKeychain.git", from: "2.0.0")

License

SwiftKeychain is released under the MIT license. See the LICENSE.txt file for more info.