CTF NO : 5
Greetings and good day! Welcome to another walkthrough. Today, we are going to solve an easy but awesome crypto challenge.
Let's get started!
Challenge Details:
Topic: Cryptography
Flag Format: IHC_CTF{}
Description:
Tom and Jerry are good friends. But they always fight.
tom divided by jerry is infinity. Do you find the flag? (This line is a hint)
Download this file:
https://drive.google.com/file/d/1UGhyjXtM4CWCtGzkOhVHtfNeDMWpNCC_/
CTF Link: https://t.me/ctf_invisiblehc/10
Solution:
After downloading the file, we found a cipher with just two words:
To solve this cryptography challenge, we need to convert the cipher to binary. Now, the question is which value we should assign to Tom and Jerry?
Given the hint "Tom divided by Jerry is infinity," we can easily deduce that Jerry's value should be 0, and Tom's value should be 1.
manually decrypting it would take a lot of time. So, we'll use the Python code:
text = input("Enter the text: ")
counter = 0
results = []
while True:
if text[counter:counter+3].lower() == "tom":
results.append("1")
counter += 3
elif text[counter:counter+5].lower() == "jerry":
results.append("0")
counter += 5
else:
break
print("".join(results))
After decrypting the binary, we got another cipher in Hex format. After Decrypt Hex