An example of using Latch (https://github.com/DanielTomlinson/Latch) to store user credentials

MyAppAccount.swift

//
// MyAppAccount
//

struct MyAppAccount {
    
    let latch = Latch(service: (NSBundle.mainBundle().bundleIdentifier ?? "com.example.MyApp"))
    
    
    var username: String? {
        get                 { return getValueForKey("username") }
        set(newObject)      { setValueForKey("username", value: newObject) }
    }
    
    var password: String? {
        get                 { return getValueForKey("password") }
        set(newObject)      { setValueForKey("password", value: newObject) }
    }
    
    
    private func getValueForKey(key: String) -> String? {
        guard let data = latch.dataForKey(key), let value = NSString(data: data, encoding: NSUTF8StringEncoding) else {
            return nil
        }
        return value as String
    }
    
    private func setValueForKey(key: String, value: String?) {
        if let value = value where value.characters.count > 0, let data = value.dataUsingEncoding(NSUTF8StringEncoding) {
            latch.setObject(data, forKey: key)
        } else {
            latch.removeObjectForKey(key)
        }
    }
    
}



// Store
var account = MyAppAccount()
account.username = "email@example.com"
account.password = "password"


// Retrieve
var account2 = MyAppAccount()
account2.username
account2.password