When you open the url (https://knightsquad.org/KCTF-2022?cypto=03MTJ3M2NjcfBDdfR2Mz42X1BTefN3MNFDdz0EMTtnRUN0S) you will see `03MTJ3M2NjcfBDdfR2Mz42X1BTefN3MNFDdz0EMTtnRUN0S` at the end. Reverse the text `03MTJ3M2NjcfBDdfR2Mz42X1BTefN3MNFDdz0EMTtnRUN0S` you will get `S0NURntTME0zdDFNM3NfeTB1X24zM2RfdDBfcjN2M3JTM30` It's base 64 encoded decode it to get flag

Original writeup (https://knightsquad.org/KCTF-2022?cypto=03MTJ3M2NjcfBDdfR2Mz42X1BTefN3MNFDdz0EMTtnRUN0S).