[CTF] B01ler_ctf - voidciphr

 

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주어지는 것은 cipher.txt인데 

내용은

PGTXD OD VXTMG XAT XFQG GA YMXAP RGXVTMAYQ X VXOOM XA XTLMVXF AGPGVMGNQ BGV RMQ FMASQ PG LXQGAVD X PVMG GB UXVTMAXFQ X PVMG PGG GB MAQMYAMBMUXAP ZGFMPMUMXAQ OGNYRP XAT ZXMT BGV OD X VMUR XAT UGVVNZP XAYFG UXAXTMXA OXASMAY UGVZGVXPMGA MABGVL NQ XFF GB RGJ GNV UGNAPVD AGJ VMQSQ TDMAY GB QPXVKXPMGA X VNLGV PRXPQ LD MAMPMXF PRGNYRP XQ M QJMPUR GBB LD VXTMG X VNLGV GV ZGQQMOFD X RGXH ZVGZXYXATX M LNVLNV XAHMGNQFD XQ PRGNYR INQP OD QXDMAY QG M LMYRP XFFXD LD TGNOPQ PDZMUXF ZGFMPMUMXAQ ZVGZXYXATX ONP ZNOFMU GZMAMGA YVXTNXFFD XOQGVOQ MP XQ X BXUP MATMKMTNXFQ QPXVP QPVNPPMAY XVGNAT JMPR QPGNP UFNOQ BGGT YFGVMGNQ BGGT MQ X UGLLGA UVD GUUXQMGAXFFD QNAY PG OXVPQ LNQMU JMPR GVTMAXVD RXVTJGVSMAY BGFS RXVXQQMAY GBBMUMXFQ OGPR FGUXF XAT AXPMGAXF XAT UNVQMAY UXZMPXFMQPQ XAT UXZPXMAQ GB MATNQPVD UGZQ QRVMAS BVGL YGMAY GNP GA AMYRP QRMBP MA LXUGA X LGO QPGVLQ X LNAMUMZXF ONMFTMAY MA VGUXTXLGNV VNBBMXAQ VGO X RXAYXV BNFF GB BGGTQPNBBQ ZMFFXYMAY PGAQ GB PNAX BMQR LMFS XAT UGUGX XQ XFQG X KXQP WNXAPMPD GB UGVA XFF GB MP XFXQ PGPXFFD NABMP BGV RNLXA UGAQNLZPMGA JMPRGNP BNQQ GV XTG XAT AXPNVXFFD JMPRGNP XAD QGVP GB PVMXF XA MATMYAXAP UVGJT RXAYQ PJAPD QMH QGFMUMPGVQ GA X RXQPMFD ONMFP QUXBBGFT MA BVGAP GB AXAUDQ FXJ UGNVPQ PRMQ AXAUD MQ X PGJA AGP X JGLXA XAT VXAQXUSQ X FGUXF IGNVAXF X TMQYNQPMAY VMYRP JMAY VXY PRXP MQ QMTMAY XYXMAQP MP NZ XAT TGJA PRMQ FXAT GB GNVQ FGGPMAY RXQ OVGNYRP TGUSQ QRGZQ XAT BXVLQ PG X KMVPNXF QPXATQPMFF

 

해당 문자열의 암호화 알고리즘을 알기 위해서, 

https://www.boxentriq.com/code-breaking/cipher-identifier

Cipher Identifier (online tool) | Boxentriq

해당사이트에서 알고리즘을 찾은 후에, 복호화 하였다.

 

XOUTCBYRMISFLAGZEVQPNKJHDW

BCTF{XOUTCBYRM}