UTCTF 2021 Beginner Cipher Gauntlet Write up

Cipher Gauntlet

 

아스키 변환

Uh-oh, looks like we have another block of text, with some sort of special encoding. Can you figure out what this encoding is? (hint: if you look carefully, you'll notice that there only characters present are A-Z, a-z, 0-9, and sometimes / and +. See if you can find an encoding that looks like this one.)
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

아랫줄 base64 decode

New challenge! Can you figure out what's going on here? It looks like the letters are shifted by some constant. (hint: you might want to start looking up Roman people).
myxqbkdevkdsyxc! iye rkfo psxscron dro loqsxxob mbizdyqbkzri mrkvvoxqo. robo sc k pvkq pyb kvv iyeb rkbn oppybdc: edpvkq{xyg_iyebo_zvkisxq_gsdr_mbizdy}. iye gsvv psxn drkd k vyd yp mbizdyqbkzri sc lesvnsxq ypp drsc cybd yp lkcsm uxygvonqo, kxn sd bokvvi sc xyd cy lkn kpdob kvv. ryzo iye oxtyion dro mrkvvoxqo!

치환문자 풀이

utflag{now_youre_playing_with_crypto}