Obfuscating Java Code

Semantic Designs can construct custom obfuscators for virtually any source language as a part of the corresponding Source Formatter. This page contains Java sample code, its obfuscated version, and the generated obfuscation map.

Java Sample Code before Obfuscation

(This is the same formatted code shown on the Java Formatter example page)


import javax.swing.JOptionPane;

public class Program1
{
  public static void main(String args[]) {
    String first,second;
    double choice;
    double radius,width,area,length;
    String value = " "; //intialize the string
    value = JOptionPane.showInputDialog("Please chose one of the options:"+"\n"+"a)Enter 1 to calculate the area of the Circle"+"\n"+"b)Enter 2 to calculate the area of the Triangle"+"\n"+"c)Enter 3 to calculate the area of the Square"+"\n"+"d)Enter 4 to calculate the area of the Rectangle"+"\n"+"e)Enter 5 to calculate the area of the Cube"+"\n"+"f)Enter 6 to exit the program");
    choice = Double.parseDouble(value);
    while (choice != 6) {
      //if(choice!=1||choice!=2||choice!=3||choice!=4||choice!=5)
      // JOptionPane.showMessageDialog(null,"Wrong option entered",  " error",
      // JOptionPane.ERROR_MESSAGE);
      if (choice == 1) { //calculate the area of circle
        first = JOptionPane.showInputDialog("Enter the value of radius");
        radius = Double.parseDouble(first);
        area = Math.PI*radius*radius;
        //print out the result
        JOptionPane.showMessageDialog(null,"The area of the Circle:    "+area,"result",JOptionPane.INFORMATION_MESSAGE);
      } else
        if (choice == 2) { //calculate the area of triangle
          first = JOptionPane.showInputDialog("Enter the value of lenght");
          second = JOptionPane.showInputDialog("Enter the value of width");
          length = Double.parseDouble(first);
          width = Double.parseDouble(second);
          area = (width*length)/2;
          JOptionPane.showMessageDialog(null,"The area of triangle:     "+area,"result",JOptionPane.INFORMATION_MESSAGE);
        } else
          if (choice == 3) { //calculate the area of square
            first = JOptionPane.showInputDialog("Enter the value of length");
            length = Double.parseDouble(first); //ge string into integer
            area = length*length;
            JOptionPane.showMessageDialog(null,"The area of the square:    "+area," result",JOptionPane.INFORMATION_MESSAGE);
          } else
            if (choice == 4) { //calculate the area of rectangle
              first = JOptionPane.showInputDialog("Enter the value of length");
              second = JOptionPane.showInputDialog("Enter the value of width");
              length = Double.parseDouble(first);
              width = Double.parseDouble(second);
              area = width*length;
              JOptionPane.showMessageDialog(null,"The area of the rectangle:     "+area,"result",JOptionPane.INFORMATION_MESSAGE);
            } else
              if (choice == 5) { //calculat the area of cube
                first = JOptionPane.showInputDialog("Enter the value of length");
                length = Double.parseDouble(first);
                area = 6*length;
                JOptionPane.showMessageDialog(null,"The area of the cube:  "+area,"result",JOptionPane.INFORMATION_MESSAGE);
              }
      value = JOptionPane.showInputDialog("Please chose one of the options:"+"\n"+"a)Enter 1 to calculate the area of the Circle"+"\n"+"b)Enter 2 to calculate the area of the Triangle"+"\n"+"c)Enter 3 to calculate the area of the Square"+"\n"+"d)Enter 4 to calculate the area of the Rectangle"+"\n"+"e)Enter 5 to calculate the area of the Cube"+"\n"+"f)Enter 6 to exit the program");
      choice = Double.parseDouble(value);
    } //end of while loop
    System.out.println("Program terminated\n");
    System.exit(0);
  } //end of main
}

Java Code after Obfuscation

Notice that comments are gone, names have been scrambled, text strings obscured. Larger constants (not shown here) have their radix twiddled. The obfuscator uses a special list provided by the user to define names that should be preserved, ensuring that public interfaces and accesses to public libraries remain valid. If you obfuscate a set of Java source files simultaneously, only the public symbols they collectively offer will be visible in the compiled source files.


import javax.swing.JOptionPane;

public class Program1
{
public static void main(String l1[]) {
String l10,O11;
double l100;
double O101,l110,l111,O1000;
String l1001 = " ";
l1001 = JOptionPane.showInputDialog("P\154\145\141se c\150o\163e\040\157ne of the \157\160\164i\157ns:" + "\012" + "\141\051\105\156t\145r\0401\040\164o\040\143alc\165late \164\150e\040\141r\145a\040of \164\150e\040C\151\162c\154e" + "\012" + "b\051Enter 2 t\157\040c\141lc\165l\141\164e the \141\162\145a\040o\146 t\150e\040Tr\151\141n\147\154e" + "\012" + "c\051Enter 3\040t\157 \143a\154\143ulate the ar\145\141 \157\146\040th\145 \123quar\145" + "\012" + "\144)\105\156\164\145r\0404\040t\157\040\143\141\154c\165\154a\164e\040t\150e\040ar\145a\040o\146 \164h\145 R\145c\164a\156g\154e" + "\012" + "\145)\105\156\164\145r\0405\040t\157\040\143\141\154c\165\154a\164\145\040\164h\145 \141\162ea\040o\146\040t\150e\040Cub\145" + "\012" + "\146)\105\156\164e\162 \066 \164o \145xit the p\162\157gr\141m");
l100 = Double.parseDouble(l1001);
while (l100 != 6) {
if (l100 == 1) {
l10 = JOptionPane.showInputDialog("\105n\164\145\162\040t\150e\040v\141\154\165\145\040o\146\040r\141\144iu\163");
O101 = Double.parseDouble(l10);
l111 = Math.PI * O101 * O101;
JOptionPane.showMessageDialog(null, "\124\150\145\040\141r\145a\040of\040\164\150e Ci\162\143l\145\072\040\040 \040" + l111, "result", JOptionPane.INFORMATION_MESSAGE);
} else
if (l100 == 2) {
l10 = JOptionPane.showInputDialog("Ent\145r\040\164\150e\040v\141l\165e \157\146\040\154en\147ht");
O11 = JOptionPane.showInputDialog("\105\156\164\145\162 \164h\145 value of\040width");
O1000 = Double.parseDouble(l10);
l110 = Double.parseDouble(O11);
l111 = (l110 * O1000) / 2;
JOptionPane.showMessageDialog(null, "T\150e area \157f\040t\162i\141\156g\154e:     " + l111, "re\163ult", JOptionPane.INFORMATION_MESSAGE);
} else
if (l100 == 3) {
l10 = JOptionPane.showInputDialog("\105\156\164\145\162 \164h\145 value\040of lengt\150");
O1000 = Double.parseDouble(l10);
l111 = O1000 * O1000;
JOptionPane.showMessageDialog(null, "\124he area \157f \164h\145 \163\161uare:    " + l111, " re\163ul\164", JOptionPane.INFORMATION_MESSAGE);
} else
if (l100 == 4) {
l10 = JOptionPane.showInputDialog("\105\156\164er t\150e\040v\141lu\145\040\157f len\147\164h");
O11 = JOptionPane.showInputDialog("E\156\164er the\040v\141l\165e \157\146 width");
O1000 = Double.parseDouble(l10);
l110 = Double.parseDouble(O11);
l111 = l110 * O1000;
JOptionPane.showMessageDialog(null, "T\150e are\141\040o\146 \164h\145 rectangle:     " + l111, "\162\145\163\165\154t", JOptionPane.INFORMATION_MESSAGE);
} else
if (l100 == 5) {
l10 = JOptionPane.showInputDialog("E\156ter t\150\145\040v\141l\165\145\040of lengt\150");
O1000 = Double.parseDouble(l10);
l111 = 6 * O1000;
JOptionPane.showMessageDialog(null, "T\150e area \157f\040t\150e\040\143\165\142e:  " + l111, "r\145sult", JOptionPane.INFORMATION_MESSAGE);
}
l1001 = JOptionPane.showInputDialog("P\154ease\040\143h\157s\145 \157ne of the options\072" + "\012" + "\141)\105\156\164e\162 \061 \164o c\141\154culat\145\040th\145 \141r\145a \157f\040th\145 \103i\162cl\145" + "\012" + "\142\051\105\156\164e\162 \062 to \143\141lculat\145\040th\145 \141re\141 \157f\040\164h\145 \124r\151an\147le" + "\012" + "c\051\105\156ter 3\040t\157 \143alc\165\154ate th\145\040ar\145a\040of\040t\150\145 \123q\165a\162e" + "\012" + "\144)Ente\162\0404\040t\157 \143alc\165\154ate th\145\040a\162\145\141\040o\146 \164\150e\040R\145c\164a\156g\154e" + "\012" + "\145)Ent\145\162 \065 \164o\040\143\141\154\143ula\164\145 \164\150\145\040a\162ea\040o\146 \164h\145 C\165b\145" + "\012" + "\146)\105\156\164e\162 \066 \164o \145\170it t\150e\040\160r\157\147r\141m");
l100 = Double.parseDouble(l1001);
}
System.out.println("\120r\157\147\162a\155 \164e\162mi\156a\164ed\012");
System.exit(0);
}
}

Obfuscated Symbol Cross Reference

The obfuscator produces a cross reference mapping obfuscated symbols to the orginal symbols, so that obfuscated code in the field can still be decoded if necessary. In fact, by reversing this map, the obfuscator can unobfuscate the code (of course, it cannot restore the comments).


Double -> Double
INFORMATION_MESSAGE -> INFORMATION_MESSAGE
JOptionPane -> JOptionPane
Math -> Math
PI -> PI
Program1 -> Program1
String -> String
System -> System
area -> l111
args -> l1
choice -> l100
exit -> exit
first -> l10
javax -> javax
length -> O1000
out -> out
parseDouble -> parseDouble
println -> println
radius -> O101
second -> O11
showInputDialog -> showInputDialog
showMessageDialog -> showMessageDialog
swing -> swing
value -> l1001
width -> l110

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Java Obfuscation
Example