Encrypted text string?

looking for a way to have an encrypted text string in a file -- the Lisp program could read it in, and then decrypt it to validate the user's installation. I suppose it could be a registry setting instead. Just some rather simple encryption, so that the user could not easily change it.
any thoughts?

--Jeremiah

 

What I do is take things like serial numbers and program ID's and run them
through my own mathematical MixMaster and then convert them to hexadecimal
strings which I then provide to the client in their personal license file. The
base program reads the file and converts the hex back to numbers to validate the
license and determine which program IDs are licensed. It's not rocket science,
but I'm betting that my system is confusing enough to prevent most from
successfully unmixing.

program could read it in, and then decrypt it to validate the user's
installation. I suppose it could be a registry setting instead. Just some
rather simple encryption, so that the user could not easily change it.

 

yeah, that's pretty much what I'm looking for. was hoping there's either an existing code library out there, or something easy translatable.
my dream choice, would be an AutoLISP version of the TEA encryption (http://www.simonshepherd.supanet.com/tea.htm) -- I just don't want to spend a good 20 hours on translating it myself.

--Jeremiah

 

That's the way it goes. I'm sure I spent a lot more than 20 hours developing my
encryption system.

existing code library out there, or something easy translatable.

(http://www.simonshepherd.supanet.com/tea.htm) -- I just don't want to spend a
good 20 hours on translating it myself.

 

DOSlib by Robert McNeel & Assoc. has a routine called dos_encrypt that does
this.

program could read it in, and then decrypt it to validate the user's
installation. I suppose it could be a registry setting instead. Just some
rather simple encryption, so that the user could not easily change it.

 

Hi,

It's a fairly good idea to include the MAC address of the computer in the
mix if you want to use it for locking the program to a computer.
MAC addresses are unique to the network card. I hash it with a program
number and strip out portions of the result such that the licence code
issued to the user cannot be used to devise the algorithm. This part of the
code only took about 20 minutes

The system is not break proof - nothing is, but for the time investment and
the likelihood of software attracting the attention of someone with the
skills to break it, the result is fairly secure.

Getting the MAC address proved to be quite difficult for and I ended up
writing the output of the MS command "IPConfig /All" to a temporary file and
reading the data from there. This took about 10 hours, by the time I tried
all sorts of code and shareware DLLs, but with this idea should take about
an hour.

--


Laurie Comerford
CADApps
www.cadapps.com.au

program could read it in, and then decrypt it to validate the user's
installation. I suppose it could be a registry setting instead. Just some
rather simple encryption, so that the user could not easily change it.

 

the MAC address is fine, but as you mention, it's incredibly difficult to get at. One would also have to be careful with users who have a laptop with a wired and wireless NIC, thus two MAC addresses.
I'm just grabbing the computer name, I can use a vl-registry function to read in HKLM\system\currentcontrolset\control\computername\computername .
So I've got each user's computername, now I just need a vague encryption of the software package / license count, so I can verify if that user can use that feature.
I've gone and translated the TEA encryption into AutoLISP (attached), but that does not want to work, as AutoLISP just can't deal with the size of numbers involved. Also too much work for the helper functions to prep everything into binary data.

How do you hash your MAC address? Something like that could be helpful. We already have a unique 12-character product install code. I would love to just find a bone simple encryption algorithm.

Even the stuff from WWII is far more than is necessary for our uses. At this point, I'm thinking more along John's lines, I'll just make a very big number out of pi, convert to a string, mix the characters around, and have something vaguely encrypted.

--J

 

Hi,

Fortunately I can't remember what I did, so I'm unlikely to reveal my
algorithm but it is something along the lines of:

Break the MAC address into its 8 characters

Multiple 1st by a primary number 4 to 8 digits
Multiple 2nd by a primary number 4 to 8 digits
Multiple 3rd by a primary number 4 to 8 digits
Multiple 4th by a primary number 4 to 8 digits
Multiple 5th by a primary number 4 to 8 digits
Multiple 6th by a primary number 4 to 8 digits
Multiple 7th by a primary number 4 to 8 digits
Multiple 8th by a primary number 4 to 8 digits

Add them all up
Strip a couple of digits of the end, multiply by the program code
Strip a couple of digits of the start and end and append a sub string of the
program code which helps me recognise the validity of the code for that
program.
All this is done in a DLL which returns a variety of strings which are then
processed in a CASE statement to determine whether the program is fully
licenced or partially licenced.

--


Laurie Comerford
CADApps
www.cadapps.com.au

get at. One would also have to be careful with users who have a laptop with
a wired and wireless NIC, thus two MAC addresses.

read in HKLM\system\currentcontrolset\control\computername\computername .

of the software package / license count, so I can verify if that user can
use that feature.

that does not want to work, as AutoLISP just can't deal with the size of
numbers involved. Also too much work for the helper functions to prep
everything into binary data.

We already have a unique 12-character product install code. I would love to
just find a bone simple encryption algorithm.

this point, I'm thinking more along John's lines, I'll just make a very big
number out of pi, convert to a string, mix the characters around, and have
something vaguely encrypted.