Rating:

In this challenge we have given this text:
>Emperor Caesar encrypted a message with his record-breaking high-performance encryption method. You are his tax collector that he is trying to evade. Fortunately for you, his crown is actually a dunce cap.
>mshn{P_k0ua_d4ua_a0_w4f_tf_ahe3z}

The format is is similar to the flag one, with four characters before a curly bracket and another curly bracket at the end.
We know that the flag must begin with "flag" and we can see that f->m, l->s, a->h, g->n are all transformations based on the Caesar cipher.
We also have the hint in the explanation because the emperor is named.
So using a Caesar cipher decrypter we obtain the flag:
```
flag{I_d0nt_w4nt_t0_p4y_my_tax3s}
```

Original writeup (https://github.com/pwnsticciotti/writeups/tree/master/redpwnCTF/dunce_crypto).