Secret Door - Misc

Task

You have found a secret door, to unlock it you must analyze the circuit design to obtain the code.

lock-diagram.png

Solution

We get the following lock-diagram.png image, containing logic circuit:

We have to open the door, therefore the output should be 1. I used logic.ly to redraw the circuit. This tool displays the current status of the lines, either 0 or 1, simplifying circuit analysis. To manipulate the inputs, I utilized buttons and placed a light bulb at the output, allowing visibility when the output was 1.

For the current state of inputs, the output is 1:

This means that for 1 to appear at the output, the input state must be as follows:

01000111

The state of the inputs is our code, which means that we get the content of the flag.

Flag:

RS{01000111}