Techniques to prevent/slow decompiling

Question

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Best Java obfuscator ?

For my example I know that eclipse offers a decompiling plugin. And I am sure there are a few other ways out there to go about decompiling programs.

I have also heard that decompiling is not 100% accurate, and the results can vary greatly(even when decoiling same program in same way). The accuracy will depend on how the code was constructed etc.

What techniques would one use to make a java (or any) program more difficult to decompile?

maybe but I am looking for hard coding techniques too(not just java) (yes I know it could get confusing) — sealz, Jul 08 '11 at 18:47
There are obfuscators, I've heard rumors they have impact on application performance. But whatever you do, at the end your code can be reverse engineered. The question is what you want to achieve? Protect yourself against some script kiddies or highly skilled software engineers :-) — home, Jul 08 '11 at 18:50
Obfuscation can only slow someone down a little... http://stackoverflow.com/questions/6481668/protecting-executable-from-reverse-engineering — trutheality, Jul 08 '11 at 18:57

score 1 · Accepted Answer · answered Jul 08 '11 at 18:41

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You can't make the program effectively more difficult to decompile. You can make it harder to understand once it's decompiled, but the decompilation process is deterministic.

answered Jul 08 '11 at 18:41

Paul Sonier

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Not true. It is possible to have valid byte code programs which do not map to valid Java sources. – Thorbjørn Ravn Andersen Jul 08 '11 at 19:04
@thorbjorn: true, but the OP was talking about ways to make a Java program difficult to decompile; by definition, if it goes through the Java compilation process, it can be decompiled. – Paul Sonier Jul 08 '11 at 19:15
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obfuscators work by transform the well known byte streams into byte streams with identifcal function which do not map to a Java program. – Thorbjørn Ravn Andersen Jul 08 '11 at 19:39

score 1 · Answer 2 · answered Jul 08 '11 at 18:42

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The number one technique is to use an obfuscator. Lots of people like ProGuard because it integrates nicely with Eclipse and is free. Also see Obfuscate4e, which works with other obfuscators as well as with ProGuard.

answered Jul 08 '11 at 18:42

Ted Hopp

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score 0 · Answer 3 · answered Jul 08 '11 at 18:41

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First result from google: http://proguard.sourceforge.net/

answered Jul 08 '11 at 18:41

sshannin

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Considered that perhaps the OP did not know that this was the word to search for? No need to be arrogant. – Thorbjørn Ravn Andersen Jul 08 '11 at 19:02

score 0 · Answer 4 · answered Jul 08 '11 at 18:44

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I've also used yGuard and it seemed to work nicely. You can integrate it into your Ant scripts fairly easily also.

answered Jul 08 '11 at 18:44

aardvarkk

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Techniques to prevent/slow decompiling

4 Answers4