Trying to use KeychainItemWrapper by Apple "translated" to Swift

Question

Sigh, I have been working on this the whole afternoon... here is my nightmare:

I am trying to use the KeychainItemWrapper made by Apple. But I "translated" its Objective-C codes to Swift:

import Foundation
import Security
class MyKeychainItemWrapper: NSObject {
var keychainItemData: NSMutableDictionary?
var genericPasswordQuery: NSMutableDictionary = NSMutableDictionary()

init(identifier: String, accessGroup: String?) {

    super.init()

    // Begin Keychain search setup. The genericPasswordQuery leverages the special user
    // defined attribute kSecAttrGeneric to distinguish itself between other generic Keychain
    // items which may be included by the same application.
    genericPasswordQuery.setObject(kSecClassGenericPassword, forKey: kSecClass)
    genericPasswordQuery.setObject(identifier, forKey: kSecAttrGeneric)

    // The keychain access group attribute determines if this item can be shared
    // amongst multiple apps whose code signing entitlements contain the same keychain access group.
    println(accessGroup)
    if (!(accessGroup == nil)) {
        genericPasswordQuery.setObject(accessGroup!, forKey: kSecAttrAccessGroup)
    }

    // Use the proper search constants, return only the attributes of the first match.
    genericPasswordQuery.setObject(kSecMatchLimitOne, forKey: kSecMatchLimit)
    genericPasswordQuery.setObject(kCFBooleanTrue, forKey: kSecReturnAttributes)

    var tempQuery: NSDictionary = NSDictionary(dictionary: genericPasswordQuery)

    var outDictionary: Unmanaged<AnyObject>? = nil

    var status: OSStatus = SecItemCopyMatching(tempQuery as CFDictionaryRef, &outDictionary)
    println(status == noErr)

    if (status == noErr) {
        // Stick these default values into keychain item if nothing found.
        resetKeychainItem()

        // Add the generic attribute and the keychain access group.
        keychainItemData!.setObject(identifier, forKey: kSecAttrGeneric)

        if (!(accessGroup == nil)) {
            keychainItemData!.setObject(accessGroup!, forKey: kSecAttrAccessGroup)
        }
    } else {
        // load the saved data from Keychain.
        keychainItemData = secItemFormatToDictionary(outDictionary?.takeRetainedValue() as NSDictionary)
    }
}

Then in my app's AppDelegate.swift, I am trying to use it by:

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
    var passwordItem: MyKeychainItemWrapper = MyKeychainItemWrapper(identifier: "Password", accessGroup: nil)
...

So, the initializer is called, but but but somehow, I ALWAYS, ALWAYS get

Thread 1: EXC_BREAKPOINT (code=EXC_ARM_BREAKPOINT, subcode=0xe7ffdefe)

I have tried commenting out the problem lines and then I get this error at another if():

I even tried:

var mmm: Bool = (accessGroup == nil)
if (!mmm) {
  genericPasswordQuery.setObject(accessGroup!, forKey: kSecAttrAccessGroup)
}

But same error at the same place, i.e. if(..)

I am now so confused. Did I miss something here or?

Environment: Xcode6-beta6, iOS 8 beta 5 on a non-jailbroken iPhone 5.

Claud

Answer 1

Swift 3

import UIKit
import Security

let kSecClassGenericPasswordValue = String(format: kSecClassGenericPassword as String)
let kSecClassValue = String(format: kSecClass as String)
let kSecAttrServiceValue = String(format: kSecAttrService as String)
let kSecValueDataValue = String(format: kSecValueData as String)
let kSecMatchLimitValue = String(format: kSecMatchLimit as String)
let kSecReturnDataValue = String(format: kSecReturnData as String)
let kSecMatchLimitOneValue = String(format: kSecMatchLimitOne as String)
let kSecAttrAccountValue = String(format: kSecAttrAccount as String)

struct KeychainAccess {

    func setPasscode(identifier: String, passcode: String) {
        if let dataFromString = passcode.data(using: String.Encoding.utf8) {
            let keychainQuery = [
                kSecClassValue: kSecClassGenericPasswordValue,
                kSecAttrServiceValue: identifier,
                kSecValueDataValue: dataFromString
            ] as CFDictionary
            SecItemDelete(keychainQuery)
            print(SecItemAdd(keychainQuery, nil))
        }
    }

    func getPasscode(identifier: String) -> String? {
        let keychainQuery = [
            kSecClassValue: kSecClassGenericPasswordValue,
            kSecAttrServiceValue: identifier,
            kSecReturnDataValue: kCFBooleanTrue,
            kSecMatchLimitValue: kSecMatchLimitOneValue
        ] as  CFDictionary
        var dataTypeRef: AnyObject?
        let status: OSStatus = SecItemCopyMatching(keychainQuery, &dataTypeRef)
        var passcode: String?
        if (status == errSecSuccess) {
            if let retrievedData = dataTypeRef as? Data,
                let result = String(data: retrievedData, encoding: String.Encoding.utf8) {
                passcode = result as String
            }
        }
        else {
            print("Nothing was retrieved from the keychain. Status code \(status)")
        }
        return passcode
    }
}

Swift 2

import UIKit;
import Security;


let kSecClassGenericPasswordValue = NSString(format: kSecClassGenericPassword);
let kSecClassValue = NSString(format: kSecClass);
let kSecAttrServiceValue = NSString(format: kSecAttrService);
let kSecValueDataValue = NSString(format: kSecValueData);
let kSecMatchLimitValue = NSString(format: kSecMatchLimit);
let kSecReturnDataValue = NSString(format: kSecReturnData);
let kSecMatchLimitOneValue = NSString(format: kSecMatchLimitOne);
let kSecAttrAccountValue = NSString(format: kSecAttrAccount);


class KeychainAccess: NSObject {

func setPasscode(identifier: String, passcode: String) {
    let dataFromString: NSData = passcode.dataUsingEncoding(NSUTF8StringEncoding)!;
    let keychainQuery = NSDictionary(
    objects: [kSecClassGenericPasswordValue, identifier, dataFromString],
    forKeys: [kSecClassValue, kSecAttrServiceValue, kSecValueDataValue]);
    SecItemDelete(keychainQuery as CFDictionaryRef);
    let status: OSStatus = SecItemAdd(keychainQuery as CFDictionaryRef, nil);
}


func getPasscode(identifier: String) -> NSString? {
    let keychainQuery = NSDictionary(
    objects: [kSecClassGenericPasswordValue, identifier, kCFBooleanTrue, kSecMatchLimitOneValue],
    forKeys: [kSecClassValue, kSecAttrServiceValue, kSecReturnDataValue, kSecMatchLimitValue]);
    var dataTypeRef: AnyObject?
    let status: OSStatus = SecItemCopyMatching(keychainQuery, &dataTypeRef)
    var passcode: NSString?;
    if (status == errSecSuccess) {
        let retrievedData: NSData? = dataTypeRef as? NSData
        if let result = NSString(data: retrievedData!, encoding: NSUTF8StringEncoding) {
            passcode = result as String
        }
    }
    else {
        print("Nothing was retrieved from the keychain. Status code \(status)")
    }
    return passcode;
   }
}

Then from anywhere simply call:

func setPasscode(passcode: String) {
    let keychainAccess = KeychainAccess();
    keychainAccess.setPasscode("YourAppIdentifier", passcode:passcode);
}


func getPasscode() -> NSString {
    let keychainAccess = KeychainAccess();
    return keychainAccess.getPasscode("YourAppIdentifier")!;
}


func deletePasscode() {
    let keychainAccess = KeychainAccess();
    keychainAccess.setPasscode("YourAppIdentifier", passcode:"");
}

Boyette

This looks really good and I'll probably use the bulk of this example. Is there a reason that you wrapped the two functions as instance methods on the class rather left them than as pure top level functions or as class methods? – Pomeranian

Also the keychainQuery variables seem to need to be NSDictionary types (I'm using Xcode 6.1.1) - NSMutableDictionary is the specific one that worked for me but non-mutable may also work. – Pomeranian

When I copy and paste that code into a class file I get errors. For example the line: var keychainQuery = [ Gives me the error: "NSString is not a subtype of NSData" – Vevay

@Boyette For kSecClass I get an error: Value of type CFString does not conform to expected element type 'NSCopying'. This is for Swift 2.0. Any idea how to fix this ? – Kaitlinkaitlyn

That works - thanks for the quick update! Why do you use let kSecClassValue = NSString(format: kSecClass); instead of let kSecClassValue = (format: kSecClass as String); ? – Kaitlinkaitlyn

@karlml - no specific reason, I was re-translating this several times since objective c times... probably it is better to change now all NSString constants to String, give it try .. – Boyette

Answer 2

official is GenericKeychain

existing several swift version, the best one is:

jrendel/SwiftKeychainWrapper · GitHub

how to use it:

1. download file: KeychainWrapper.swift

2. write code to set/get/delete:

   let StrUsernameKey:String = "username"
   let StrPasswordKey:String = "password"
   
   let saveSuccessful: Bool = KeychainWrapper.setString(usernameTextField.text!, forKey: StrUsernameKey)
   print("saveSuccessful=\(saveSuccessful)") //saveSuccessful=true
   let retrievedString: String? = KeychainWrapper.stringForKey(StrUsernameKey)
   print("retrievedString=\(retrievedString)") //retrievedString=Optional("yourLastStoredUsernameString")
   let removeSuccessful: Bool = KeychainWrapper.removeObjectForKey(StrUsernameKey)
   print("removeSuccessful=\(removeSuccessful)") //removeSuccessful=true
   let retrievedStringAfterDelete: String? = KeychainWrapper.stringForKey(StrUsernameKey)
   print("retrievedStringAfterDelete=\(retrievedStringAfterDelete)") //retrievedStringAfterDelete=nil
   

Nesselrode

Answer 3

Updates for Swift 2.

Here is an example implementation that may help.:

import Security

class ZLKeychainService: NSObject {

    var service = "Service"
    var keychainQuery :[NSString: AnyObject]! = nil

    func save(name name: NSString, value: NSString) -> OSStatus? {
        let statusAdd :OSStatus?

        guard let dataFromString: NSData = value.dataUsingEncoding(NSUTF8StringEncoding) else {
            return nil
        }

        keychainQuery = [
            kSecClass       : kSecClassGenericPassword,
            kSecAttrService : service,
            kSecAttrAccount : name,
            kSecValueData   : dataFromString]
        if keychainQuery == nil {
            return nil
        }

        SecItemDelete(keychainQuery as CFDictionaryRef)

        statusAdd = SecItemAdd(keychainQuery! as CFDictionaryRef, nil)

        return statusAdd;
    }

    func load(name name: NSString) -> String? {
        var contentsOfKeychain :String?

        keychainQuery = [
            kSecClass       : kSecClassGenericPassword,
            kSecAttrService : service,
            kSecAttrAccount : name,
            kSecReturnData  : kCFBooleanTrue,
            kSecMatchLimit  : kSecMatchLimitOne]
        if keychainQuery == nil {
            return nil
        }

        var dataTypeRef: AnyObject?
        let status: OSStatus = SecItemCopyMatching(keychainQuery, &dataTypeRef)

        if (status == errSecSuccess) {
            let retrievedData: NSData? = dataTypeRef as? NSData
            if let result = NSString(data: retrievedData!, encoding: NSUTF8StringEncoding) {
                contentsOfKeychain = result as String
            }
        }
        else {
            print("Nothing was retrieved from the keychain. Status code \(status)")
        }

        return contentsOfKeychain
    }
}

//Test:
let userName = "TestUser"
let userValue: NSString = "TestValue"
print("userName: '\(userName)'")
print("userValue: '\(userValue)'")

let kcs = ZLKeychainService()

kcs.save(name:userName, value: userValue)
print("Keychain Query \(kcs.keychainQuery)")

if let recoveredToken = kcs.load(name:userName) {
    print("Recovered Value: '\(recoveredToken)'")
}

Output:

userName: 'TestUser'
userValue: 'TestValue'
Keychain Query [acct: TestUser, v_Data: <54657374 56616c75 65>, svce: Service, class: genp]
Recovered Value: 'TestValue'

Tracery

Thanks for the help. I figured out a workaround that works for now. But this problem may still remains. – Claud

@HillInHarwich why does this solution not work for you? – Tracery

@ileonard It did not work for me - but the reason (as I found out typically soon after posting to here) was that I was using another project - and although I had added the framework/project to the normal list, I had not added put the frame work in the "Include in binary" list - the proper name of which escapes me now. – Botulinus

Answer 4

My solution seems working:

init(identifier: String) {

    super.init()

    genericPasswordQuery.setObject(kSecClassGenericPassword, forKey: kSecClass as String)
    genericPasswordQuery.setObject(identifier, forKey: kSecAttrGeneric as String)

    // Use the proper search constants, return only the attributes of the first match.
    genericPasswordQuery.setObject(kSecMatchLimitOne, forKey: kSecMatchLimit as String)
    genericPasswordQuery.setObject(kCFBooleanTrue, forKey: kSecReturnAttributes as String)

    var tempQuery: NSDictionary = NSDictionary(dictionary: genericPasswordQuery)

    var outDictionary: Unmanaged<AnyObject>? = nil

    let status: OSStatus = SecItemCopyMatching(tempQuery as CFDictionaryRef, &outDictionary)
    var result: NSDictionary? = outDictionary?.takeRetainedValue() as NSDictionary?
    if (result == nil) {
        // Stick these default values into keychain item if nothing found.
        resetKeychainItem()

        // Add the generic attribute and the keychain access group.
        keychainItemData!.setObject(identifier, forKey: kSecAttrGeneric as String)

    } else {
        // load the saved data from Keychain.
        keychainItemData = secItemFormatToDictionary(result!)

    }
}

The only thing I did is to unwrap the outDictionary immediately after getting it.

Claud