TiTouchId.swift

import Foundation
import UIKit
import LocalAuthentication

public class TiTouchId {
    var context: LAContext?
    
    init() {
        context = LAContext()
    }
    
    func isSupported() -> Bool {
        var error: NSError?
        
        let currentOSSupported: Bool = UIDevice.currentDevice().systemVersion.compare("8.0", options: .NumericSearch) != .OrderedAscending
        let touchIDSupported: Bool = context!.canEvaluatePolicy(.DeviceOwnerAuthenticationWithBiometrics, error: &error)
        
        return currentOSSupported && touchIDSupported
    }
    
    func authenticate(reason: String, callback: (NSMutableDictionary) -> ()) -> Void {
        context?.evaluatePolicy(.DeviceOwnerAuthenticationWithBiometrics, localizedReason: reason, reply: {(success, error) in
            callback([
                "success": success,
                "error": (error?.localizedDescription)!,
                "code": (error?.code)!
            ])
        })
    }
}

ViewController.swift

let touchId = TiTouchId()
if (touchId.isSupported()) {
    touchId.authenticate("Please verify to continue", callback: {(attrs) in
        let success: Bool = attrs.valueForKey("success") as! Bool
        
        NSLog("Success - %d", success)

        if ((attrs.valueForKey("error")) != nil) {
            NSLog("Error - %@", attrs.valueForKey("error") as! String)
            NSLog("Code - %lu", attrs.valueForKey("code") as! Int)
        }
    })
} else {
    NSLog("Touch ID is not supported on this device")
}