Re: Java and avoiding software piracy?

From:
Joshua Cranmer <Pidgeot18@verizon.net>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 11 Jul 2007 21:35:06 GMT
Message-ID:
<e2cli.13269$g44.9907@trnddc02>
On Wed, 11 Jul 2007 00:27:30 +0000, adamorn wrote:

Hi,

Im *hoping* to release an application that I developed in Java, and I
want to release a free version as well as a pay version.


Put only what pertains to the free version in the free version. Don't
even try to have the free version be the pay version with the features
locked out. The pay-only features MUST NOT BE PRESENT IN THE BYTECODE /AT
ALL./ Then only distribute the pay version after people order it.

Clearly I want to be able to avoid people cracking it, or creating key
generators... Although i know that it is unlikely to actually stop them
entirely.. I want to do as much as I can to ensure that IF they want to
crack/keygen it, that it will be as difficult as possible.


You're trying to do what just about every major software company is
trying (and failing) to do. Simple online license key verification would
be sufficient; if you're really willing to go far, some code sanity tests
for verification (involving java bytecode assembly and knowledge of
obscure parts of the Java VM specification) would probably trip up 90% of
decompilers. Then again, nesting a few synchronized, finally, conditional
break/continue, and loop statements is practically guaranteed to trip up
a decompiler.

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