Should I use Excel for this software project--or something else?

[Gerald Abrahamson]

I designed, developed, and implemented a productivity software program
in BASIC over 20 years ago (pre-dates Excel and Lotus 123). The
software was not written on an IBM PC-compatible computer, nor am I
aware of it ever being transferred to a PC-compatible system. I did
not write it in Visicalc because I preferred the control and
error-checking available in BASIC that Visicalc did not offer.

The program was very successful for the business, as they based their
purchasing volume on that program. Costs dropped dramatically and the
company survived while many competitors did not. However, that was 20+
years ago. I believe the company no longer exists, as they are no
longer listed in telephone directories or anywhere on the Internet.

I have searched on the Internet and have not found a comparable
program--although simple textbook versions of this software have been
available for some time (including one from Microsoft).

The program is *not* business- or industry-specific and does not
contain any proprietary information about any business. The only
unique item in the program is the mathematical formula I created to
generate the results. Mathematical formulae can not be patented, thus
I can not protect it that way. Copyright/trademark would generally
only apply to a specific work--which could be easily ripped off.

I have created a 3-sheet Excel97 spreadsheet that incorporates my
formula, and it behaves according to the same rules of the original
BASIC program. I have also added easily-changable variables that were
not readily available in the original BASIC program.

I am considering licensing this productivity software on a per-seat
basis, and would like to protect the mathematical formula I created in
order to maximize revenue from it.

I am guess-estimating a per-seat price of US $50, and perhaps 10k to
20k seats. Volume might go higher if there are significant
international sales, which could be easily managed. On-line sales will
be likely, as the program is quite small (largest version is 125k).

Based upon what I have read, Excel is not a very secure program.

I will be using sheet-protection on sheet 1 (management data) and
sheet 3 (results page--data taken from sheets 1 and 2). No protection
on sheet 2, as this is the variable data entered to make the
calculations.

Based on the above information, which software package would you
recommend as a way to relatively securely distribute and run the
software and keep it from being pirated? I am not required to use
Excel, it is simply what I have available--so I use it.

Regards, Jerry

 

[Michael J. Malinsky]

You are correct, Excel is not very secure. Although password protection is
available for workbooks and macros, there are many utilities available on
the net that can crack the passwords.

For maximum security, I would suggest creating your application in a
programming environment, such as Visual Basic or C or whatever you might be
more comfortable with. I've never used either, but I'm sure whatever
application developed using one of those, or something like them, can be
made more secure than Excel.

Mike.

 

[Arne]

Even though making an executable using a compiler like VB
or C or Delphi will make it more difficult to track the
mathematical formula, there exist decompilation programs
which probably make it relatively easy to find out how
things are computed.

I think that an important point that you should take
account of, is the fact that many people around the world
use Excel (whether we like that or not), and that it
greatly improves the ease-of-use if you distribute Excel-
compatible applications. Maybe you can combine the two by
trying to hide your magic formula in a DLL or something
which can then be used in combination with Excel. In this
newsgroup however, you can see that problems with home-
made DLL's are quite common, but I have never tried it
myself. Maybe expert advice

 

[Keith Willshaw]

Based on the above information, which software package would you
recommend as a way to relatively securely distribute and run the
software and keep it from being pirated? I am not required to use
Excel, it is simply what I have available--so I use it.

Regards, Jerry

I'd suggest VB.Net or if you are somewhat more adventurous
C# which is much wasier for the beginner to pick up than C++

Be aware that a simple port of an old style basic program isnt
the best way to go. Unlike the old basic implementations
VB is an object orientated language.

However you should know that there are some issues with
security issues with vb.net. Essentially its raher easy to
disassemble the cod and get access to VB source. There
are a number of code obfuscation tools available to prevent this.

Keith