Un réveil difficile
In this challenge, we are given this CIRC file. When we open it with Logisim, we can see the following:
As we can see in the challenge statement, we need to print Un_c. So we just modify the input matrix by clicking on the 0s to modify them into 1s:
Now that we have Un_c as specified we need to use CTRL+T to tick the clock and get the message printed out:
We need to do that several times until we get back to Un_c:
Now we have everything we need to assemble the flag. As specified in the challenge statement, if we don’t know what character is printed, we need to choose in this order number, lower case, and finally upper case.
So with all that said, the flag is 404CTF{Un_cH1FFrA9e_A55e2_bi3n_d3PreCie}