Swift Keychain class ( supported Xcode 6.0.1 )

Keychain.swift

import UIKit
import Security

class Keychain {
    
    class func save(key: String, data: NSData) -> Bool {
        let query = [
            kSecClass as String       : kSecClassGenericPassword as String,
            kSecAttrAccount as String : key,
            kSecValueData as String   : data ]
        
        SecItemDelete(query as CFDictionaryRef)
        
        let status: OSStatus = SecItemAdd(query as CFDictionaryRef, nil)
        
        return status == noErr
    }
    
    class func load(key: String) -> NSData? {
        let query = [
            kSecClass as String       : kSecClassGenericPassword,
            kSecAttrAccount as String : key,
            kSecReturnData as String  : kCFBooleanTrue,
            kSecMatchLimit as String  : kSecMatchLimitOne ]
        
        var dataTypeRef :Unmanaged<AnyObject>?
        
        let status: OSStatus = SecItemCopyMatching(query, &dataTypeRef)
        
        if status == noErr {
            return (dataTypeRef!.takeRetainedValue() as NSData)
        } else {
            return nil
        }
    }
    
    class func delete(key: String) -> Bool {
        let query = [
            kSecClass as String       : kSecClassGenericPassword,
            kSecAttrAccount as String : key ]
        
        let status: OSStatus = SecItemDelete(query as CFDictionaryRef)
        
        return status == noErr
    }
    
    
    class func clear() -> Bool {
        let query = [ kSecClass as String : kSecClassGenericPassword ]
        
        let status: OSStatus = SecItemDelete(query as CFDictionaryRef)
        
        return status == noErr
    }
    
}

KeychainTests.swift

import UIKit
import XCTest

class KeychainTests: XCTestCase {
    
    override func setUp() {
        super.setUp()
        Keychain.clear()
    }
    
    override func tearDown() {
        Keychain.clear()
        super.tearDown()
    }
    
    func testSaveLoad() {
        let key1 = "testSaveLoadKey1"
        let key2 = "testSaveLoadKey2"
        let saveData = "data".dataValue
        
        XCTAssertTrue(Keychain.load(key1) == nil)
        XCTAssertTrue(Keychain.load(key2) == nil)
        
        XCTAssertTrue(Keychain.save(key1, data: saveData))
        
        XCTAssertTrue(Keychain.load(key1) != nil)
        XCTAssertTrue(Keychain.load(key2) == nil)
        
        let loadData = Keychain.load(key1)!
        
        XCTAssertEqual(loadData.stringValue, saveData.stringValue)
    }
    
    
    func testDelete() {
        let key1 = "testDeleteKey1"
        let key2 = "testDeleteKey2"
        let saveData = "testDeleteData".dataValue
        
        XCTAssertTrue(Keychain.save(key1, data: saveData))
        XCTAssertTrue(Keychain.save(key2, data: saveData))
        
        XCTAssertTrue(Keychain.load(key1) != nil)
        XCTAssertTrue(Keychain.load(key2) != nil)
        
        XCTAssertTrue(Keychain.delete(key1))
        
        XCTAssertTrue(Keychain.load(key1) == nil)
        XCTAssertTrue(Keychain.load(key2) != nil)
    }
    
    func testClear() {
        let key = "testClearKey"
        let data = "testClearData".dataValue
        
        Keychain.save(key, data: data)
        XCTAssertTrue(Keychain.load(key) != nil)
        
        Keychain.clear()
        XCTAssertTrue(Keychain.load(key) == nil)
    }
    
}

extension String {
    public var dataValue: NSData {
        return dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)!
    }
}

extension NSData {
    public var stringValue: String {
        return NSString(data: self, encoding: NSUTF8StringEncoding)!
    }
}