Author Topic: Can you recommend Lisp encrpytion software  (Read 12857 times)

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septicad

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Re: Can you recommend Lisp encrpytion software
« Reply #15 on: April 04, 2008, 01:37:24 PM »
Se7en
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Well you can make your own loader; not that hard, ive made one or two

loader?? - are you saying an EXE with an encryption algorithm - linked to an application start.

Keith™

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Re: Can you recommend Lisp encrpytion software
« Reply #16 on: April 04, 2008, 01:38:14 PM »
IntelliCAD can use just about any lisp that AutoCAD can use. IntelliCAD also has the ability to use C++ compiled languages as well. I suspect the reasopn people don't actively develop on that platform is due to the fact that there is a much larger target audience in AutoCAD .. not to mention that almost all AutoCAD lisp programs will work flawlessly on IntelliCAD. There are a few deviations in DCL that I have noted and had the occasion to convert over for clients, but those were limited and really were quite simple corrections in the file formatting that made them work as desired.
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Keith™

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Re: Can you recommend Lisp encrpytion software
« Reply #17 on: April 04, 2008, 01:42:26 PM »
Se7en
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Well you can make your own loader; not that hard, ive made one or two

loader?? - are you saying an EXE with an encryption algorithm - linked to an application start.

You can devise your own encryption/decryption scheme and then use a custom loader in AutoCAD to load the encrypted lisp into memory, so yes it is entirely possible. You could conceivably encrypt the lisp to a scheme of your choosing, then add that encrypted file as a resource in a VLX. Of course you would have to deliver the custom loader to the client .. this provides another level of complexity to the project. All they need to do then is crack the loader and they will be able to encrypt/decrypt your lisp files without problem.

The lesson here is that there is nothing that is completely safe ... only more or less safe when compared to other methods.
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septicad

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Re: Can you recommend Lisp encrpytion software
« Reply #18 on: April 04, 2008, 02:07:53 PM »
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You can devise your own encryption/decryption scheme and then use a custom loader in AutoCAD to load the encrypted lisp into memory, so yes it is entirely possible. You could conceivably encrypt the lisp to a scheme of your choosing, then add that encrypted file as a resource in a VLX. Of course you would have to deliver the custom loader to the client .. this provides another level of complexity to the project. All they need to do then is crack the loader and they will be able to encrypt/decrypt your lisp files without problem.

The lesson here is that there is nothing that is completely safe ... only more or less safe when compared to other methods.

I have already released my software to people with the PROTECT method... i knew it didn't provide full protection. But i'm selling my very specialized septic design software to people who know ZERO cad and it mainly used by IntelliCAD/Bricscad users because of $, but there are a couple AutoCAD and LandDesktop users.  So VLX is out.

My important assumption is: They don't know about UNPROTECT + they would have to significantly change the look of the end product to make it so I couldn't figure it out someday.

So my situation was make 0$ or get some $$, recoup some of my R&D time and risk that someone will figure it out...

With that said... if i could add a second level of protection i would take the time to investigate this...  so Keith if you could be a little more descriptive regarding the "loader" , particularly one that could be made x-platform.

Thanks
Steve

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Re: Can you recommend Lisp encrpytion software
« Reply #19 on: April 04, 2008, 03:00:25 PM »
Well, lets say you build an arx/drx module that is loaded in Intellicad that merely loads your program from an encrypted state ..

Your arx/drx (or whatever the flavor of development platform IntelliCAD is currently using) finds your encrypted lisp program. It could be called whatever you wanted it to be called, not necessarily lsp. Then decrypts it into a temp file, loads it into memory and deletes the temp file .. you don't need the .lsp file once it is loaded. The user would never have a readable version of the file to work with.
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septicad

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Re: Can you recommend Lisp encrpytion software
« Reply #20 on: April 04, 2008, 03:28:27 PM »
keith, this is what i though you were getting at.  Thanks for the clarification.

Steve

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Re: Can you recommend Lisp encrpytion software
« Reply #21 on: April 04, 2008, 04:15:34 PM »
FAS and VLX is different from "AutoCAD Protected Lisp"
There are many "AutoCAD Protected Lisp" unencryptors available on the internet ..
Sorry Se7en, but FAS is a compiled resource, VLX is not .. VLX contains compiled FAS files and uncompiled DCL files. Currently there is one known program to decompile FAS into assembly language with bits and pieces of lisp thrown in for good measure, but there is no known complete reversal program available. It makes FAS vulnerable, but not without considerable effort. VLX is vulnerable but only so much as a person would have to separate the resource into various FAS and DCL files.
so what if it has extra ASCI attached...?! The guts of the format of both are the same scheme. `Compiled' in the VLIDE terms is basically just `substitution' (I should say that the word substitution isnt really a good term either but it will do for the purposes of this discussion.).

You can write a VLX/FAS `decompiler' with Autolisp i bet.

The separation of a FAS/DCL/ETC `from' a VLX is in the header!
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Keith™

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Re: Can you recommend Lisp encrpytion software
« Reply #22 on: April 04, 2008, 04:27:40 PM »
You can write a VLX/FAS `decompiler' with Autolisp i bet.
Nope .. AutoLisp does not support the writing of null characters. I have also done extensive research on the FAS format. It is indeed a compiled format in machine code, just as a C++ executable or dll is a compiled format in machine code. You probably have never seen the correlation of FAS and machine code before so I don't fault you.

Incidently FAS is far more secure than anything in .NET
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JohnK

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Re: Can you recommend Lisp encrpytion software
« Reply #23 on: April 08, 2008, 09:15:09 AM »
I dont understand what you are saying. ...granted its been a while since ive looked into the FAS format (Im sure they have ``changed the algorithm''--or something else cool sounding--since then) but I did at one time look into the format; (alert "HELLO") => (HELLO alert)

As a test: Compile a line of code. Open the FAS in a hex editor, the first few lines (three or four) should be a header explaining how many strings can be found in the file/function and an offset to the length of the code or something like that (Blah, blah, blah). Open the VLX, (if you have `diff'' available do that) you will find the very same header a few lines down (three or four) from the VLX header.  I should try out this test before i post this, in case im off my rocker but i dont really care.

I would have to find my old notes or just pick up the subject again from scratch but I seriously doubt much has changed and to be honest, I have little interest in doing any further research on the topic. I can get what I want with a question on theswamp why would I want to spend my time decompiling.

dotnet is something i will have to get into later. But to spur a thought; i can understand peoples initial reaction to it being able to be cracked, but why so adamant about it. Maybe, ``open your code up'' and reap the benefits of potential return favors.  Or dont worry about your code cause `Joe' doesnt own a compiler and doesnt care to see how button one works. Or know that Cracker `Bob' only wants to change the string that says ``click here to do this'' to ``rock and roll tootsie pop!'' and he can do that in a hex editor. ...
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ElpanovEvgeniy

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Re: Can you recommend Lisp encrpytion software
« Reply #24 on: April 09, 2008, 12:35:55 AM »
You excuse me, that I interrupt, but compiler VLX => FAS => LSP already is...  :-(

hyposmurf

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Re: Can you recommend Lisp encrpytion software
« Reply #25 on: May 01, 2008, 05:09:57 PM »
i use a safenet superpro usb dongle to control unauthorised usage of my lisp prog in my office. i compile my lisp into fas / vlx and with the api provided by the superpro dongle, and having a routine in the lisp , i check for the existence of the usb dongle key. if its not there, exit and the usern cannot use the lisp prog at all.



I was just about to come back with a question about protecting my lisp files via a protected USB stick.Ive looke at their site and I cant find a pric on thre for anything.My guess is they will be out my budget.I've also got to work out how on earth I can convert my lisp to VLX format in the api? :-o .Is there a way to just have files on a USB only accesible via AutoCAD on my PC and if they are opened they are encrypted?I'm finding that I have prying eyes ,sifting through my PC.
« Last Edit: May 01, 2008, 05:16:18 PM by hyposmurf »

hyposmurf

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Re: Can you recommend Lisp encrpytion software
« Reply #26 on: May 01, 2008, 05:20:33 PM »
Wait, hold on a sec!

Do you want these `encrypted' lisp files to work in autocad?
OR
Is this just a way to protect your source code in between COMPILING?

NOTE:
Converting a LSP to VLX, FAS is called compiling so i use that word instead of `ENCRYPTING' even though `COMPILE' usually means to ``convert to machine code blah, blah''.
Yes I'd like the encrypted files to work in CAD.If I could protect them while compiling that would be good but not as important.I'd like to use something rather than nothing at the moment.Even if it isnt amazingly secure,in the meantime I work on finding something better.