how to Commercially Licence Java Software? [closed]_问答_开发者

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I have开发者_开发技巧 written a Desktop based accounting software in Java. I want to put a key or licence or other kind of security to prevent redistribution of the software by the client. I just want to know how to go about it?

The short answer: DRM doesn't stop piracy. It only hurts your paying customers. It doesn't really matter what you do.

The best you can do is set up a simple product-key system, all that really does is makes your application not able to be copied quickly with no work, it doesn't really harm your paying customers but don't expect it to stop anyone who's determined not to pay for your software.

The best thing you can do is make your software good. This gives people incentive to actually purchase it. Also a fair pricing plan helps (There's a reason Adobe / Microsoft software are highly pirated).

First, lets leave alone the commercial/GPL war out of SO and actually answer the OP's question...

I work for a company selling protected Java software. Our software is good. It actually rocks and completely owns the competition's offerings. If users aren't happy with our protection scheme, they can go use the inferior products our competitors are making.

The thing is: we're moving to a more and more networked world. Our software mandates an Internet connection for some functionalities to work correctly (the software will launch without an Internet connection, but not everything will work correctly).

A correctly designed server/client protection scheme, where sufficiently enough processing happens on the server side, cannot be pirated. At one point, it becomes easier to rewrite the software than to try to reproduce what's happening on the server side.

You can think of it this way: nobody ever succeeded playing on the real "World of Warcraft" servers with a pirated or keygen'ed licence (there have been fake servers but that would be missing the point: people playing on rogue servers are not playing in the real economy, which is a massive fail).

Or this way: nobody has pirated GMail. GMail definitely rocks: it's probably the app I use the most (after my IDE). Sure, it's free... But nobody can clone it: nearly everything is happening on the server side.

It is very common in some software circles to have restrictive copy protection in place: it was hardware dongles back in the days now it's mostly server/client scheme. For example there are a lot of very good and very expensive software thare are using the "Flex license manager", including expensive C++ compiler that beat the crap out of anything free (or cheap), which some companies are very happy to shell out big $$$ for and very happy to have the ability to buy such a software (and they don't mind needing an internet connection for the license verification).

So, to answer your question:

I want to put a key or licence or other kind of security to prevent redistribution of software by the client. I just want to know how to go about it?

Go about it by puttin a client/server key verification in place. Ideally, make part of the computation your desktop software is doing happen on the server side: that gives headaches to wannabe pirates (they either have to pirate your server or to reproduce what the server does, there's simply no other way around it).

Here's a +7 upvotes answer I made to a similar question which gives more detail:

Making commercial Java software (DRM)

For online software, you can request the email address and first and last name from the buyer. You can apply an algorithm on those values to turn them into a large number. You prompt the user to enter the number, and if the calculated number matches what was entered by the user, you store the number and enable the software.

I use Plimus, which is a service that delivers my software and bills the customers for me. I store the key generator on their server, which generates the serial number based on the information from the customer's online order.

For shrink wrapped (off-the-shelf) software, you could still do this, but you'll need some type of online activation mode that basically forces the user to register when they first run it. This allows you to collect the email address and name and send them their serial number. Users typically don't like this. What if your server is down? However, they'll be willing to do it if your software is good enough and you provide decent support to help them with problems registering.

For off the shelf software, typically, some algorithm is used to generate a series of large numbers, each of which matches some algorithm and enables the software. One serial number is packaged with each copy of the software.

In my opinion, the most difficult issue is providing the user the ability to try the software out. You could offer refunds, but you'll need a way to revoke the software. You could have a trial version, but trial software is even harder because you don't want to let them keep using the trial version. It's simpler to create a free (forever) limited version, and the pay version has additional features.

Use of java is tempting to many as it is rapid and does not demand geeklike skills to code. But i dont think you can DRM your apps successfully made in Java. To recover from this mistake start coding with C/C++ from now on.