How safe are P-code files?
in [Matlab]
|
From: Jan Simon on 17 Jun 2010 11:12 Dear Dan! > i'm not trying to hide any passwords. just an entire function M-file. As you see in the cited thread, you can hide the function, but you cannot hide the actions which happen during execution. It is always possible to go through your P-coded function line by line and overload all toolbox functions. In conclusion, it is safe to hide actions inside a single line and using symbols, which cannot be overloaded as TRY, CATCH, END, IF, SWITCH, RETURN, ... (see: ISKEYWORD). E.g. a password check can be: a = input('Password', 's'); switch a, case 'thepassword', otherwise return; end *in one line*. Nevertheless you can use an external debugger together with setting the memory manager to the debug mode to read string tables of the P-file loaded to the memory. Then you'd probably find 'thepassword' in clear text. Nevertheless, this level of debugging is not easy anymore and by such tricks even the magic DVD key 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0 was revealed although the idustry spend millions to hide it. Is it really a benefit for you or the users/customers if the code is obfuscated? If so, are there any problems in p-coding all your functions? Kind regards, Jan
From: dan berkowitz on 17 Jun 2010 11:53 Thank you for the reply Jan. Yes, it is of tremendous benefit to me if the code is all obfuscated. I am trying to pcode ALL the functions M-files. Perhaps that will help? db
From: Jan Simon on 17 Jun 2010 15:05 Dear Dan! > Thank you for the reply Jan. Yes, it is of tremendous benefit to me if the code is all obfuscated. I am trying to pcode ALL the functions M-files. Perhaps that will help? It is your decision if P-coding is helpful. The possibilities to find and fix bugs in P-coded files are really limited. Maintaining such code is challenging. Do you have any problems with P-coding all your files? Jan
From: dan berkowitz on 17 Jun 2010 18:54
that's the direction i'm considering: p-coding all function M-files and the script invoking all the M-files. think that will do the trick? i'm planning on maintaining the code on one computer, and keeping only the p-coded files on the production computers. any thoughts would be appreciated. regards, db |