HTB - Low Logic

Walkthrough for Low Logic - Hackthebox

Description

I have this simple chip, I want you to understand how it's works and then give me the output.

Challenge Link : https://app.hackthebox.com/challenges/Low%2520Logic

Challenge

After downloading the zip file, we can unzip it with "hackthebox" password, and then we see an input.csv file and a chip.jpg file

ok, this is my first hardware challenge and I dont' have much clue on what to do here, but someone hinted me to look at how the transistors are used to construct logic gates. After googling for a while, I found this page which talks about it. The interesting ones were the AND / OR gates. Here's how the AND gate look like

AND gate

only if both the inputs are high (1) , then the bulb is lit (output is 1), else 0. Then there is the OR gate where if either of them are conducting (1) , then the output is 1, and is 0 only if both of the inputs are 0.

OR gate

It then became easy to figure out the similaritess of our picture and the gates and I came to this conclusion.

so with this, we now know what to perform with the given inputs. It would be something like this

So I wrote a small python script to do that for me with the given inputs and then print the output.

with open("input.csv", "r") as f:
    lines = f.readlines()[1:]

output = ""

for line in lines:
    in0, in1, in2, in3 = map(int, line.strip().split(","))
    output += str((in0 & in1) | (in2 & in3))

print(output)

Seems like binary, I used cyberchef to convert it back and got the flag. GGs !