License / Registration key enabled software

[T]

We all know that there are many softwares that require some license key
or registration key to enable them. How does one implement something
like this in python?

[James Stroud]

Re: License / Registration key enabled software

T wrote:

We all know that there are many softwares that require some license key
or registration key to enable them. How does one implement something
like this in python?
>

Here's a thought: AES encrypt the bytecode dynamically for each user,
using as a key an sha hash of their personal and corporate information,
ethernet hardware address, and some hardware specific information, such
as the serial number of the diskdrive on which the software will be
installed. Along with this dynamically encrypted version of the
software, require them to save the personal and corporate information in
the system registry or equivalent on their computer. Then write a C or
Fortran extension that assembles this information on the client side,
produces the hashed key and uses it to decrypt the bytecode real-time,
when the program launches. This bytecode can be fed to a running python
process via a pipe and executed through skilled use of the marshal module.

Once you have implemented this system, license it to software vendors
such as Microsoft (or better yet, scientific software companies). Please
remember to pay me royalties in the sum of 20% gross profits for
devising this system for you.

James

--
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/

[T]

Re: License / Registration key enabled software


Umm...I was hoping for something simpler and more straight forward. Is
there a module that would be useful for this type of thing?

[Steven D'Aprano]

Re: License / Registration key enabled software

On Sat, 23 Sep 2006 18:39:58 -0700, T wrote:

>
Umm...I was hoping for something simpler and more straight forward. Is
there a module that would be useful for this type of thing?

It really helps if you quote the relevant bits of the email you are
replying to. Otherwise, people who come along and see your post will ask
"Simpler than what? Module useful for what sort of thing? What is this
luser talking about?"

To implement a licence/registration key system in Python, you should first
answer a couple of simple questions:

Q1. Is my software so precious and special that users will put up with the
inconvenience and nuisance value of registration keys?

If the answer is No, then don't use registration keys. Find a different
model to make money: give the software away and charge for support, or
something. Using registration keys won't bring in money for you if your
users just stop using the software and use a competing product instead.

If the answer is Yes, then go on to question 2:

Q2. Are you sure?

If the answer is still Yes, then read this and see if it helps:

http://en.wikipedia.org/wiki/Keygen

--
Steven.

[Sybren Stuvel]

Re: License / Registration key enabled software

T enlightened us with:

We all know that there are many softwares that require some license
key or registration key to enable them. How does one implement
something like this in python?

Why do you want to? I've never seen software successfully protected by
such schemes. If you really want to protect your software, turn it
into a web application/service.

Sybren
--
Sybren Stüvel
Stüvel IT - http://www.stuvel.eu/

[Lawrence D'Oliveiro]

Re: License / Registration key enabled software

In message <1158951061.539 594.164040@i3g2 000cwc.googlegr oups.com>, T wrote:

We all know that there are many softwares that require some license key
or registration key to enable them. How does one implement something
like this in python?

Reliably? Can't be done, in Python or any other language.

[Lawrence D'Oliveiro]

Re: License / Registration key enabled software

In message <1159061998.460 873.321180@m73g 2000cwd.googleg roups.com>, T wrote:

>Umm...I was hoping for something simpler and more straight forward.

It cannot be done simply or straightforward ly. Or reliably, for that matter.

[Steven D'Aprano]

Re: License / Registration key enabled software

On Mon, 25 Sep 2006 22:54:58 +1200, Lawrence D'Oliveiro wrote:

In message <1158951061.539 594.164040@i3g2 000cwc.googlegr oups.com>, T wrote:
>

>We all know that there are many softwares that require some license key
>or registration key to enable them. How does one implement something
>like this in python?

>
Reliably? Can't be done, in Python or any other language.

Of course it can -- you can rely on it to be cracked.

Oh the other hand, for some uses, a partial success is better than none at
all. (Personally, I don't believe that registration keys are necessarily
one of those, but that's not up to me to decide.)



--
Steven D'Aprano

[Mike Playle]

Re: License / Registration key enabled software

On Fri, 22 Sep 2006 11:51:01 -0700, T wrote:

We all know that there are many softwares that require some license key
or registration key to enable them. How does one implement something
like this in python?

Here's a slightly different take on license keys that
nobody else has mentioned:

License keys exist to make it easier for honest users to
remain honest. Since any scheme can be cracked, dishonest
users will use your software without paying for it with
or without a license key scheme, so there's no point
spending much effort on the dishonest. Focus instead on
what your honest users want.

For instance a customer might want to buy a license to
use your software on up to 5 machines at once, but still
have the software installed on every machine in the
company. License systems like FlexLM can work here, to
make it easier for them to ensure that they comply with
the terms of the license.

Forget about the people who'll crack your software. Ask
yourself whether a license key scheme offers anything
to the people who won't try to crack it. If it does, then
actually implementing the scheme becomes trivial; if it
doesn't, then leave it out, because it won't help against
crackers.

Mike

[Robert Kern]

Re: License / Registration key enabled software

Mike Playle wrote:

For instance a customer might want to buy a license to
use your software on up to 5 machines at once, but still
have the software installed on every machine in the
company. License systems like FlexLM can work here, to
make it easier for them to ensure that they comply with
the terms of the license.

But then you must weigh that against the inconvenience that you impose upon your
customers. Although you may make it easier for them to comply with your license,
you are also making it harder for them to *use* your software.

I do not know a single person who has used FlexLM-licensed software and does not
hate FlexLM with a burning passion.

--
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco

[Ben Finney]

Re: License / Registration key enabled software

Mike Playle <usenet@vfx.org .ukwrites:

License keys exist to make it easier for honest users to remain
honest.

What doubletalk. If usage restrictions were in *any* way what end users
wanted, they'd choose software that has it over software that does
not.

Usage restrictions serve *no* want of the end user.

For instance a customer might want to buy a license to use your
software on up to 5 machines at once, but still have the software
installed on every machine in the company.

This need is adequately served by not imposing usage restrictions. Any
effective imposition of usage restrictions is hostile to the wants of
the user.

If usage restrictions are brought into the picture, it is to serve the
wants of someone else, *not* the end user. It is disingenuous to
suggest otherwise.

License systems like FlexLM can work here, to make it easier for
them to ensure that they comply with the terms of the license.

This is describing a want of the copyright holder, *not* the end user.

Forget about the people who'll crack your software. Ask yourself
whether a license key scheme offers anything to the people who won't
try to crack it. If it does, then actually implementing the scheme
becomes trivial; if it doesn't, then leave it out, because it won't
help against crackers.

Very sound advice, I agree entirely.

--
\ "If you're not part of the solution, you're part of the |
`\ precipitate." -- Steven Wright |
_o__) |
Ben Finney

[Steve Holden]

Re: License / Registration key enabled software

Ben Finney wrote:

Mike Playle <usenet@vfx.org .ukwrites:
>
>

>>License keys exist to make it easier for honest users to remain
>>honest.

>
>
What doubletalk. If usage restrictions were in *any* way what end users
wanted, they'd choose software that has it over software that does
not.
>
Usage restrictions serve *no* want of the end user.
>

No, but usage reporting is very important to large organisations with
enterprise copies of their applications. They want to stay in
compliance, and it's notoriously hard to track usage.

>

>>For instance a customer might want to buy a license to use your
>>software on up to 5 machines at once, but still have the software
>>installed on every machine in the company.

>
>
This need is adequately served by not imposing usage restrictions. Any
effective imposition of usage restrictions is hostile to the wants of
the user.
>
If usage restrictions are brought into the picture, it is to serve the
wants of someone else, *not* the end user. It is disingenuous to
suggest otherwise.
>

So you're suggesting that most people would rather be dishonest?

Otherwise you might as well say that any costs associated with using a
piece of software (including purchase pricing) are "hostile to the wants
of the user".

>

>>License systems like FlexLM can work here, to make it easier for
>>them to ensure that they comply with the terms of the license.

>
>
This is describing a want of the copyright holder, *not* the end user.
>

I think your view is a little biased here.

>

>>Forget about the people who'll crack your software. Ask yourself
>>whether a license key scheme offers anything to the people who won't
>>try to crack it. If it does, then actually implementing the scheme
>>becomes trivial; if it doesn't, then leave it out, because it won't
>>help against crackers.

>
>
Very sound advice, I agree entirely.
>

As do I. The sad thing is that the people most concerned about
protection of intellectual property are often the ones whose IP is least
likely to need protection.

regards
Steve
--
Steve Holden +44 150 684 7255 +1 800 494 3119
Holden Web LLC/Ltd http://www.holdenweb.com
Skype: holdenweb http://holdenweb.blogspot.com
Recent Ramblings http://del.icio.us/steve.holden

[Mike Playle]

Re: License / Registration key enabled software

On Thu, 28 Sep 2006 10:19:37 +1000, Ben Finney wrote:

>For instance a customer might want to buy a license to use your
>software on up to 5 machines at once, but still have the software
>installed on every machine in the company.

>
This need is adequately served by not imposing usage restrictions. Any
effective imposition of usage restrictions is hostile to the wants of
the user.

Who is "the user"? The person who uses the software isn't always
the same as the person who paid for it, or the person who'll be
in trouble if the license terms aren't adhered to.

Imagine you're an IT manager for a medium-to-large company who
wants to use some expensive piece of software. You talk to the
vendor and buy a licence to use the software on up to 5 machines
at once, but you don't know who in the company will want to use
it, so for convenience you want to install it on every PC in the
building.

Having installed it all over the shop, how can you be sure that
only 5 people are using it at any one time? Do you expect your
users to walk round the building asking everyone else if they're
using the software, or are they more likely to just start it up
and start working?

Of course this argument really applies only to large, expensive
commercial packages. I'd certainly agree that licence keys are
often used inappropriately in a way which doesn't really benefit
anyone, but this doesn't mean they don't have a place somewhere
in the grand scheme of things.

Mike

[Mike Playle]

Re: License / Registration key enabled software

On Wed, 27 Sep 2006 12:21:08 -0500, Robert Kern wrote:

Mike Playle wrote:

>For instance a customer might want to buy a license to
>use your software on up to 5 machines at once, but still
>have the software installed on every machine in the
>company. License systems like FlexLM can work here, to
>make it easier for them to ensure that they comply with
>the terms of the license.

>
But then you must weigh that against the inconvenience that you impose upon your
customers. Although you may make it easier for them to comply with your license,
you are also making it harder for them to *use* your software.

This is certainly true.

As with any other software feature it's vital to weigh up the
advantages against the disadvantages, and not blindly add
features which don't provide a clear overall benefit.

I do not know a single person who has used FlexLM-licensed software and does not
hate FlexLM with a burning passion.

Yup, I can agree with that. From the POV of the guy who just
wants to get some work done, it's usually a real pain.

His boss may have a different view of the matter, though.
I've met people who've _bought_ FlexLM-licensed software
who think it's the best thing since sliced bread.

Mike

[Sybren Stuvel]

Re: License / Registration key enabled software

Steve Holden enlightened us with:

Otherwise you might as well say that any costs associated with using
a piece of software (including purchase pricing) are "hostile to the
wants of the user".

It's true. People pay because they have to, but they'd rather not.

Sybren
--
Sybren Stüvel
Stüvel IT - http://www.stuvel.eu/