1. How Protector4J works

    Protector4J protects your java source code by converting jar files into private encrypted jarx files, we take multiple approaches to ensure the security of your application from both the JVM and binary level, providing high-strength application protection.

  2. The issues with code obfuscation

    Due to the high semantics of JVM bytecode, it is extremely easy to analyze and read. It is easy to analyze its running logic by using dynamic debugging. Writing a dynamic debugging tool is not a very complicated task. Therefore, obfuscation is not a reliable protection solution.

  3. The issues with class encryption

    Due to the existence of JVM attachment mechanism, all so-called encrypted code that has not been detached from normal JVM operation can be easily read using attachment tools. Therefore, this is the most ineffective protection solution.

  4. The issues with VM protection

    Virtualization protection is the most secure code protection method, but due to its significant impact on performance, it cannot be applied to all code in a program. It can only protect critical code, while other code still carries the risk of exposure. By targeting other parts of the code, one can obtain functional information about the virtualized portion of the code.

  5. The issues with AOT compilation

    AOT compilation is difficult to configure and compile, and it has a high probability of failing. Even if the compilation is successful, the code logic only changes from bytecode representation to machine code representation. Its inherent operational logic still exists without any special protection. If one can understand its own compilation and execution mechanism, it is still possible to reverse engineer readable code.

  6. Deobfuscation with vlx-vmengine

    Deobfuscate Java code with JVM bytecode execution engine vlx-vmengine

  7. JVM bytecode execution engine written in Java/Kotlin

    Traditional Java dynamic debugging can only be done based on the source code, and without source code or obfuscated Java class files, dynamic debugging is impossible. The running of Java programs is based on the JVM, and the JVM uses bytecode as the basis for execution. We use Kotlin to construct a JVM bytecode execution engine, which can be used with modern IDEs, such as IDEA, to debug Java programs at the bytecode level to observe the running behavior of the program.

  8. GraalVM NativeImage Reverse Engineering

    For Java programs that have entered the era of binary compilation, can their code be easily reverse-compiled just like in the era of bytecode? What are the characteristics of binary files compiled by NativeImage? Is the strength of binary compilation sufficient to protect important code? In order to explore the above issues, I recently wrote a NativeImage analysis tool that has achieved a certain level of reverse derivation.

  9. Hacking into an Encrypted Java Application with jhsdb (HotSpot Debugger)

    One solution for Java code protection is encrypting the class files. Such solutions load encrypted class or jar files via a custom classloader, Due to the existence of JVM's Attach Mechanism, this method is not effective and can be easily cracked with tools that are included in the JDK.

  10. Extracting Java Class Information from AOT-Compiled Binaries

    AOT is also considered a solution for Java code protection, but unfortunately, many Java programs now cannot be separated from the framework. Due to the complexity of the framework, even programs compiled by AOT must include class information in the final generated binary file, and the class files are actually arranged neatly in the resource area of the binary file.

  11. What is JARX file

    JARX file is our proprietary archive file format, which uses the same Deflate compression algorithm as Zip and AES encryption algorithm to encrypt the data.

  12. The Best Java Code Protection Solution Beyond Obfuscation

    Encrypting your code protects your intellectual property and greatly enhances the security of your applications. It makes IP theft, code tampering, and discovery of security vulnerabilities so involved and expensive that a casual snoop armed with a free Java decompiler won't do.

  13. Excelsior JET Alternative

    Protector4J is more than just an Excelsior JET replacement