Save and retrieve value via KeyChain

Question

I'm trying to store an Integer and retrieve it using KeyChain.

This is how I save it:

func SaveNumberOfImagesTaken()     {         let key = "IMAGE_TAKEN"         var taken = 10         let data = NSKeyedArchiver.archivedDataWithRootObject(taken)         let query : [String:AnyObject] = [             kSecClass as String : kSecClassGenericPassword,             kSecAttrAccount as String : key,             kSecValueData as String : data         ]         let status : OSStatus = SecItemAdd(query as CFDictionaryRef, nil)      } 

This is how I try to retrieve it:

func CheckIfKeyChainValueExitss() -> AnyObject? {     var key = "IMAGE_TAKEN"     let query : [String:AnyObject] = [         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 let op = dataTypeRef?.toOpaque() {         let data = Unmanaged<NSData>.fromOpaque(op).takeUnretainedValue()         if let string: AnyObject? =  NSKeyedUnarchiver.unarchiveObjectWithData(data) as? AnyObject? {             if key == "IMAGE_TAKEN"             {                 return string as! String!              }             else if string == nil             {                 return nil             }         }     }     return nil  } 

I'm getting the following error:

Could not cast value of type '__NSCFNumber' to 'NSString'

I tried playing with the variables but without success.

Answer 1

I've update Eric's version for Swift 5:

class KeyChain {      class func save(key: String, data: Data) -> OSStatus {         let query = [             kSecClass as String       : kSecClassGenericPassword as String,             kSecAttrAccount as String : key,             kSecValueData as String   : data ] as [String : Any]          SecItemDelete(query as CFDictionary)          return SecItemAdd(query as CFDictionary, nil)     }      class func load(key: String) -> Data? {         let query = [             kSecClass as String       : kSecClassGenericPassword,             kSecAttrAccount as String : key,             kSecReturnData as String  : kCFBooleanTrue!,             kSecMatchLimit as String  : kSecMatchLimitOne ] as [String : Any]          var dataTypeRef: AnyObject? = nil          let status: OSStatus = SecItemCopyMatching(query as CFDictionary, &dataTypeRef)          if status == noErr {             return dataTypeRef as! Data?         } else {             return nil         }     }      class func createUniqueID() -> String {         let uuid: CFUUID = CFUUIDCreate(nil)         let cfStr: CFString = CFUUIDCreateString(nil, uuid)          let swiftString: String = cfStr as String         return swiftString     } }  extension Data {      init<T>(from value: T) {         var value = value         self.init(buffer: UnsafeBufferPointer(start: &value, count: 1))     }      func to<T>(type: T.Type) -> T {         return self.withUnsafeBytes { $0.load(as: T.self) }     } } 

---

I've update Eric's version for Swift 3:

class KeyChain {      class func save(key: String, data: Data) -> OSStatus {         let query = [             kSecClass as String       : kSecClassGenericPassword as String,             kSecAttrAccount as String : key,             kSecValueData as String   : data ] as [String : Any]          SecItemDelete(query as CFDictionary)          return SecItemAdd(query as CFDictionary, nil)     }      class func load(key: String) -> Data? {         let query = [             kSecClass as String       : kSecClassGenericPassword,             kSecAttrAccount as String : key,             kSecReturnData as String  : kCFBooleanTrue,             kSecMatchLimit as String  : kSecMatchLimitOne ] as [String : Any]          var dataTypeRef: AnyObject? = nil          let status: OSStatus = SecItemCopyMatching(query as CFDictionary, &dataTypeRef)          if status == noErr {             return dataTypeRef as! Data?         } else {             return nil         }     }      class func createUniqueID() -> String {         let uuid: CFUUID = CFUUIDCreate(nil)         let cfStr: CFString = CFUUIDCreateString(nil, uuid)          let swiftString: String = cfStr as String         return swiftString     } }  extension Data {      init<T>(from value: T) {         var value = value         self.init(buffer: UnsafeBufferPointer(start: &value, count: 1))     }      func to<T>(type: T.Type) -> T {         return self.withUnsafeBytes { $0.pointee }     } } 

Example usage:

let int: Int = 555 let data = Data(from: int) let status = KeyChain.save(key: "MyNumber", data: data) print("status: ", status)  if let receivedData = KeyChain.load(key: "MyNumber") {     let result = receivedData.to(type: Int.self)     print("result: ", result) }