Advanced obfuscation techniques make de-compiled Java programs not re- compilable, thus to crack the target. mechanism of AspectJ [2] to render code obfuscation and string [15] Roubtsov, V., Cracking Java byte-code encryption, . Difficult to implement. – Of little benefit: The bytecode has to run! • No public/ private crypto offered. – Can it be implemented? • String encryption uses XOR type. string encryption. The latest version was released June 23, [14]. JBCO The Java ByteCode Obfuscator is built on top of the Soot framework and operates.

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Numerous code optimizations are performed at compile time. Unfortunately, this approach is fundamentally flawed, because the JVM may not load and execute encrypted classesperiod. Okay, so software-only bytecode encryption makes little sense, and the use of hardware has its own issues and is not always possible.

This site uses cookies. But before I move on, a word of caution:.

The slowdown ranges from 1. Posted on February 7, The method also generates a kind of hwid and issues a web request to the login server using a horrible case switch taking about lines, but I will spare you that.

However, care must be taken when using this feature, because a method or field may also be accessed using JNI or reflection, and it is not possible to reliably detect all such accesses even by analyzing the running program. Those are required to get meaningful jn traces. It sparked quite some discussion and confusionso Boaz had later written an essay explaining what that result really means, in his opinion.


That’s true and definitely interesting.

Protect Your Java Code — Through Obfuscators And Beyond

Thomborson, or the more recent Revisiting Sncryption Protection by P. A Gun is a Great Equalizer: Bytecode optimizations supported by some obfuscators include constant expression evaluation, assignment of static and final attributes, inlining of simple methods such as getters and setters, peephole optimizations, and so on. Remote must trigger the name obfuscator’s exclude mechanism.

Back then, the slowdown factors ranged from 3.

Protect Your Java Code – Through Obfuscators and Beyond

But any bytecoode designed to run on third-party systems has to include or be accompanied with the respective decryption key and hence may not be protected through encryption. It has to get set somewhere, does it? Moreover, any protection scheme based on bytecode encryption can be defeated without reverse engineering of the decryption routines.

But that is not necessarily what an attacker might want to achieve. Programs are statically linked, and metaprogramming facilities reflection are absent in the core language. Was the above article useful?

An obfuscator may however be capable of replacing some of the basic Java APIs with custom, obfuscated implementations. Introduction As the title suggestes, this post will feature a practical example of cracking obfuscated Java code, namely Allatori 4.

How about making the bytecode less comprehensible? With public key crypto, the key doing the decrypting needs to be stored somewhere again. Suppose your proprietary Java source triggers an annoying bug in your favorite IDE, and you have decided to reduce your source code to a test case.


If you want some theory and controversy, the paper ” On the Im possibility of Obfuscating Programs ” by Boaz Barak et al, found in the 21st Annual International Cryptology Conference Proceedings, proves that obfuscation is impossible. For the reverse engineering of the JVM to get the private key Finally, sophisticated algorithms may also be protected through mathematics transformation.

Drop me an email if you know of a tool worth adding to this list. Of course, it would be applicable to concrete cases not eclipse and only sensible classes would be encrypted election of the developer, of course. I have selected the SciMark 2.

How do you imagine it? The method iterates through the strings characters backwards and performs XOR and AND bit-operations on them — the result gets stored in a array which then gets converted and returned as a string. To understand what this means you need to know that Java source code, unlike e. To find out more, including how to control cookies, see here: You are commenting using your Facebook account.