I have a Swift framework which I'm building via Xcode 13.4.1 for distribution to third parties (BUILD_LIBRARY_FOR_DISTRIBUTION is enabled).
I am trying to protect the intellectual property and security of my framework by ensuring all internal/debug symbols are stripped prior to distribution (i.e. maximum stripping).
Therefore, after I build the framework, I apply the following command:
strip -u -r -no_code_signature_warning MyFramework.framework/MyFramework
I have found that this strips most of the symbols, however I have also noticed that it does not strip the name and properties of any of my Swift classes, they are still visible in the binary if I use a disassembler (e.g. Hopper) then I can see the class name and property names:
For example, if I have the following code:
class MySecretClass {
private let mySecretVar: String
}
Then I can see in the binary a reference something like:
objc_ivar_offset__TtC6MyFramework14MySecretClass_mySecretVar:
And Hopper will even partially re-construct the class definition for me:
00000000000de27b db 0x00 ; '.'
; class MyFramework.MySecretClass {
; let mySecretVar: Swift.String
; }
Despite the reference to objc_ivar_offset in the binary, these properties are not @objc and it's not clear to me why the compiler is including the names of the class or properties.
Things I have tried:
- Making the properties
private - Making the class
final - Marking the properties
@nonobjc
None of these work - the binary still contains the class & property names.
This definitely seems ObjC-related for all the above reasons, plus I have noticed that the binary doesn't contain any names for my structs, but I can't seem to figure out how to either prevent the compiler from emitting the names, or configure the strip command to strip the symbols after release.
I know there are third-party tools which can obfuscate variable names but I was hoping to achieve adequate symbol stripping without resorting to third-party tools.
Is there anyone with a lower-level understanding of all this able to help? Thanks!
