from the doc: BRUTE and BRUTESAV are programs designed to perform a brute force keysearch on S/MIME messages encrypted with 40-bit RC2. The following files are included:brute.exe - a Win32 console-based application (meaning that you must run it at a command prompt under Windows 95 or NT) that is the main brute force searcherbrutesav.scr - a Win32 screen saver version of the same thingb64tobin.exe - converts a Base64 encoding to its binary equivalent. This will be used to convert an S/MIME message into a form we can use.parse.exe - takes a binary S/MIME message and strips out the ASN.1 formatting, resulting in raw ciphertext for brute.exe's use.prep.bat - just combines b64tobin and parse into a single stepstartpt.exe - creates an initial starting point for brute. See the comments on 'Picking a Start Point' below.starttbl.bin - a data file for startpt.exe.test.exe - will create a test file of the same form as the output of parse.exe, used to make sure brute.exe can actually decrypt things.
b64tobin.exebrute.exeparse.exestartpt.exetest.exe