Challenge
What is 0x3D (base 16) in decimal (base 10).
Hint
Submit your answer in our competition’s flag format. For example, if you answer was ’22’, you would submit ‘picoCTF{22}’ as the flag.
Solution
Like Let’s Warm Up, this problem is similar and has multiple solutions that I will go through. First, we must understand that base 16 is hexadecimal and base 10 is decimal. Therefore we are looking for a hex to decimal conversion of “3D” to decimal. Keep in mind the 0x lead signifies the value is a hex value, and is not factored into any calculations.
Method 1: Online Converter
Again, RapidTables is a good site to use for a conversion this simple. It gives quite a bit of additional information as well.
Converting the hex can also be done by hand, by looking at an ASCII table:
Method 2: Python
The Python method comes in handy when you’re already writing scripts in the language, or you want one of the quickest ways to convert. In Python3, you can simply type the literal hex value with the 0x indicator as such:
Python2 is the same command, just be aware that you have to use “print” if doing such from the console.
Method 3: Bash
Knowing how to use commands in bash is very helpful, especially when things like python may not be installed on the shell you’re working with. Here’s a quick look at a bash script that will take hex and convert it to decimal:
Flag
The flag, in pico format, is picoCTF{61}
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