picoCTF - 2warm

Description

Name	2warm
Event	picoCTF 2019
Category	General Skills
Difficulty	Easy

The objective for this challenge is to convert the decimal value 42 to its binary value.

There is multiple ways to solve it, programatically or by pen and paper.

Pen and Paper

To solve this challenge using pen and paper, you divide 42 by 2 until you reach 0 and keep track of the remainder.

42 / 2 = 21  Remainder: 0
21 / 2 = 10  Remainder: 1
10 / 2 =  5  Remainder: 0
 5 / 2 =  2  Remainder: 1
 2 / 2 =  1  Remainder: 0
 1 / 2 =  0  Remainder: 1

Once you have finished the division you count the remainder bottom to top.
Decimal 42 = Binary 101010

Python

To convert 42 into binary using python we use the bin() function.
The bin() will convert an integer number to a binary string prefixed with “0b”.

dec = 42
binary = bin(dec)

print(binary[2:])

Java

To do this in Java we use the Integer.toBinaryString() method.

public class DecimalToBinary {
    public static void main(String[] args) {
        int decimalNumber = 42;
        String binary = Integer.toBinaryString(decimalNumber);
        
        System.out.println("Decimal Number: " + decimalNumber);
        System.out.println("Binary Equivalent: " + binary);
    }
}

Flag

To complete the challenge you need to surround the binary value with picoCTF{********} and submit the flag.