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Author's profile photo Former Member

Challenge 4

Reverse Engineering challenge and a very very very easy one…

Download the file from:

Password for downloading the file: challenge4

To run the file: java -jar “Challenge 4.jar”

or double click on the .jar in windows.

The goal is to figure out what is the password

Every 3 attempts you will be blocked for 30 seconds…


If you like this challenge, you can try “Rafael Reverse Engineering challenges” at:


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      Author's profile photo Martin English
      Martin English

      I used zip to extract the classes from Chalenge4.jar, but you still need to know a bit about how the java compiler stores strings 🙂

      Author's profile photo Former Member
      Former Member
      Blog Post Author

      To solve this easy challenge you can do the following:

      1. Go to Java decompiler online

      2. Upload the .jar file "challenge4.jar"

      3. Then, you can see all jar content


      4. Inside the you could see: