SwiftShield | Protects iOS Apps Against Reverse Engineering Attacks

Reverse engineering can be done on any software or application. An attacker can modify your source code to crack the license, inject malicious code, clone the apps and more. But if you are an iOS apps developer you can protect your iOS apps with Swift. This tool will protect the apps against reverse engineering attacks.

Swift/OBJ-C Obfuscator

SwiftShield is a tool that generates irreversible, encrypted names for your iOS project’s objects (including your Pods and Storyboards) in order to protect your app from tools that reverse engineer iOS apps, like class-dump and Cycript.

class fjiovh4894bvic: XbuinvcxoDHFh3fjid {
   func cxncjnx8fh83FDJSDd() {
     return vPAOSNdcbif372hFKF()   

Automatic mode (Swift only)

With the -automatic tag, SwiftShield will use SourceKit to automatically obfuscate entire projects (including dependencies). Note that the scope of SwiftShield’s automatic mode is directly related to the scope of Xcode’s native refactoring tool, which doesn’t refactor everything yet. While the specific cases on the document won’t be obfuscated, SwiftShield will obfuscate all Swift classes and methods that can be reverse-engineered. Take a look at the Example project to see SwiftShield in action!

Manual mode (Swift/OBJ-C)

If you feel like obfuscating absolutely everything – including typealiases and internal property names, you can also use Manual mode. This is the easiest way of running SwiftShield, but also the most time consuming. When used, SwiftShield will obfuscate properties and classes based on a tag of your choice at the end of it’s name. For example, after running SwiftShield in manual mode and a tag __s , the following code:

class EncryptedVideoPlayer__s: DecryptionProtocol__s {
 func start__s() {
    let vc__s = ImportantDecryptingController__s(secureMode__s: true)   
    vc__s.start__s(playAutomatically__s: true) 


class fjiovh4894bvic: XbuinvcxoDHFh3fjid {
  func cxncjnx8fh83FDJSDd() {
    let DjivneVjxrbv42jsr = vPAOSNdcbif372hFKF(vnjdDNsbufhdks3hdDs: true)
    DjivneVjxrbv42jsr.cxncjnx8fh83FDJSDd(dncjCNCNCKSDhssuhw21w: true) 

Deobfuscating encrypted Crash logs

After successfully encrypting your project, SwiftShield will generate an output folder containing a conversionMap.txt file containing all the changes it made to your project. allowing you to pinpoint what an encrypted object really is.

//  SwiftShield
//  Conversion Map
//  Automatic mode for MyApp 2.0 153, 2018-09-24 10.23.48


ViewController ===> YytSIcFnBAqTAyR
AppDelegate ===> uJXJkhVbwdQGNhh
SuperImportantClassThatShouldBeHidden ===> GDqKGsHjJsWQzdq

You can use this file to automatically deobfuscate any kind of text-based crash file by running:

swiftshield -deobfuscate CRASH_FILE -deobfuscate-map PATH_TO_CONVERSION_MAP



Automatic mode:

Note: Xcode 11 changed how arguments are passed to the compiler, so this tool might not work correctly outside of the legacy build mode.

If one or more modules/extensions of your app fail to satify these conditions, you can avoid obfuscating them with the -ignore-modules argument.

  • No logic based on class/property names, like loading MyClass.xib because String(describing: type(of:self)) is 'MyClass' .
  • No Objective-C classes that call Swift methods (Swift classes that call Objective-C methods are fine, except when interfacing is involved)
  • Latest Swift version and Xcode command line tools (works on all versions, but might have different results due to different SourceKit versions)
  • Make sure your project doesn’t contain one of SourceKit’s bugs. Although the bugs won’t prevent the project from being obfuscated, some of them might require some manual fixing afterwards.

(App Extensions that use NSExtensionPrincipalClass or variants in their Info.plist (like Rich Notifications/Watch apps) will have such references obfuscated as well, but will assume that you haven’t changed them from their default $(PRODUCT_MODULE_NAME).ClassName value. If you modified these plists to point to classes in different modules, you’ll have to manually change them after running this tool.)

Manual mode:

Make sure your tags aren’t used on things that are not supposed to be obfuscated, like hardcoded strings.


Warning: SwiftShield irreversibly overwrites all your source files. Ideally, you should have it run only on your CI server, and on release builds.

Download the latest release from this repository and click here to see how to setup SwiftShield.

Running SwiftShield

Automatic mode

swiftshield -automatic -project-root /app/MyApp -automatic-project-file /app/MyApp/MyApp.xcworkspace -automatic-project-scheme MyApp-AppStore

Required Parameters:

  • -automatic : Enables automatic mode.
  • -project-root : The root of your project. SwiftShield will use this to search for your project files.
  • -automatic-project-file : Your app’s main .xcodeproj/.xcworkspace file.
  • -automatic-project-scheme myScheme : The main scheme to build from your -automatic-project-file .

Optional Parameters:

  • -ignore-modules : Prevent certain modules from being obfuscated, separated by a comma. Use this if a certain module can’t be properly obfuscated. Note that this should be the exact name of the imported module (not the target name!). Example: MyLib,MyAppRichNotifications,MyAppWatch_Extension
  • -show-sourcekit-queries : Prints queries sent to SourceKit. Note that they are huge and will absolutely clutter your terminal, so use this only for bug reports and feature development!

Manual mode

swiftshield -project-root /app/MyApp

Required Parameters:

  • -project-root : The root of your project. SwiftShield will use this to search for your project files, storyboards and source files.

Optional Parameters:

  • -tag : Uses a custom tag. Default is __s .

Aditional parameters for both modes

  • -verbose : Prints additional information.
  • -obfuscation-character-count : Set the number of characters that obfuscated names will have. By default, this is 32 . Be aware that using a small number will result in slower runs due to the higher possibility of name collisions.
  • -dry-run : Does not actually overwrite the files. Useful for debugging!