SafeOPL

Short: SafeOPL 1.0 - Protect OPL progs against RevTran Author: Richard Smedley <rsmedley@cix.co.uk> Type: Util (S3a, S3c, Sienna) SafeOPL 1.0 (C) Richard Smedley 1997 rsmedley@cix.co.uk SafeOPL is a freeware program for the Psion S3a/S3c/Sienna which protects your OPL programs against being decompiled by programs like RevTran. It consists of two parts: An OPL template that you need to use for writing your OPL programs, and the main SafeOPL program which patches the code in the template to protect your OPO/OPA files against RevTran. It doesn't require you to use OPP or anything similar, and the software runs entirely on your Psion so you *don't* have to transfer files to a desktop computer (PC, Amiga, etc) in order to patch them. INSTALLATION ------------ Copy the following files into these directories on your Psion: SAFEOPL.OPA -> \APP\ (on any drive) SAFEOPLT.OPL -> \OPD\ (this needs to be on the internal drive) Next, select any of the files under your OPL icon to run the OPL editor, and then press Psion-O to load a new file. Use the file selector to select the \OPD\SAFEOPLT.OPL file, and then load it. Now, press Psion-D to save this as your default OPL template. You can now press Psion-X to exit the OPL editor. Finally, press Psion-I to install the SafeOPL.OPA file onto the system screen. Et voila, everything is installed! PROTECTING YOUR OPL PROGRAMS ---------------------------- Once everything has been installed, just write your OPL programs as you would normally. Use the supplied MAIN proc as the first proc of your OPL program. Make sure that you don't change anything in the START proc or write any new procs above the main: proc, it might not work properly if you do! Once you've compiled your finished program into an OPO/OPA file, run the SafeOPL program and select your file in the file selector. It will then create a second file called P<filename> (eg. "pmyfile.opa"), in which part of the code from the template has been patched with a randomly-generated code. If RevTran tries to decompile this nonsense-code, it will almost certainly crash (often quite spectacularly). However, here's the downside: Because it's patching your program with a completely random code, you may occasionally find that the code it generates *can* be decompiled (into something nonsensical) by RevTran. So you really need to have a copy of RevTran handy that you can use to confirm for yourself that your p<file>.opa file genuinely is RevTran protected. If it turns out that it isn't protected, then all you have to do us run SafeOPL again on your original OPO/OPA file to produce another p<file>.opa file. Once you've protected your file, you can erase the original OPO/OPA file and rename the p<file>.opa to remove the "p" from the beginning of the filename. SafeOPL was used to protect itself against RevTran. Feel free to test its effectiveness by trying to decompile it with RevTran! COPYRIGHT & DISTRIBUTION ------------------------ This program is freeware, but remains Copyright (C) Richard Smedley 1997. It may be freely distributed for non-commercial purposes providing all the original files remain fully intact and unmodified. Standard disclaimer applies; you use this program at your own risk. Freeware/shareware programs which have been protected with SafeOPL can be freely distributed without needing to contact me, but it would be nice if you could give me a credit somewhere in your docs. :-) If you want to use SafeOPL to protect a commercial program, then you need to contact me to obtain permission. This will probably involve nothing more than you mentioning me in the manual and sending me a free copy of the finished product. CONTACTING THE AUTHOR --------------------- If you have any comments or if you want to contact me for any reason, then here is my address: Richard Smedley PO Box 59 Sutton-In-Ashfield Notts NG17 3HP England rsmedley@cix.co.uk http://www.cix.co.uk/~rsmedley/psion.html If you find this program *really* useful then postcards, keyrings, five pound notes, naughty photos of your wife :-) etc can also be sent to me at that address... You'll find a complete collection of all my Psion programs on my home page at the above URL. VERSION HISTORY --------------- V1.0 (27.10.97) - The first release.