WinACE encrypts files (using one of its 8 methods) into a file with the extension .xef. I'd want to see some documentation on this file format but I couldn't find anything...

I'm particularly interested to know:

  • How the file is stored
  • Which of the eight encryption algorithms it actually used to create the file
  • What key it used (128-bit, 160-bit, 256-bit, etc.)

How can that information be retrieved from the file?


1 Answer 1


According to wikipedia:

Packing of ACE files is licensed as proprietary information and only available through WinACE, while Unpacking of ACE files is supported by a number of third-party archivers. However, virtually all of them (the ones that support ACE 2.x format) do this by using the proprietary "Unace.dll" from e-merge GmbH.

In the WinACE site you can read that using that .DLL you have:

The downloadable distribution of UnACE.DLL contains the 32bit .DLL, a list of function calls as well as some function prototypes, structures and constants to include when using the .DLL.

So, perhaps using it you can retrieve those informations.

  • So basically you suggest I reverse engineer a bit that unace.dll?
    – Count Zero
    Commented Aug 21, 2012 at 5:17
  • First, you could ask the WinACE developers if they would like to give you that information. If they don't get you what you need, and it's allowed by the laws where you do live, you could try reverse engineer. Commented Aug 21, 2012 at 12:51

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