CTF-safer-than-rot13-writeup

safer-than-rot13

题目信息

附件：

cry100

XMVZGC RGC AMG RVMG HGFGMQYCD VT VWM BYNO, NSVWDS NSGO RAO XG UWFN AF
HACDGMVWF. AIRVFN AII AMG JVRRVC-XVMC, FYRBIG TVIZ ESV SAH CGQGM XGGC
RVMG NSAC A RYIG TMVR NSG SVWFG ESGMG NSGO EGMG XVMC WCNYI NSG HAO
FVRG IVMH JARG MVWCH NV NAZG NSGR VTT NV EAM. OVWM TIAD YF "CV NSYF
YF CVN JMOBNV RO HGAM", YC IVEGMJAFG, EYNS WCHGMFJVMGF YCFNGAH VT
FBAJGF, FWMMVWCHGH XO NSG WFWAI "TIAD" NAD ACH JWMIO XMAJGF. GCUVO.

解题思路

1.根据题目名称提示，考虑使用rot13解码

cat cry100 | tr A-Z N-ZA-M >out.txt

2.解码后，发现依然没有有用的信息，尝试进行词频分析https://quipqiup.com/

KZIMTP ETP NZT EIZT UTSTZDLPQ IG IJZ OLAB, AFIJQF AFTB ENB KT HJSA NS
UNPQTZIJS. NVEISA NVV NZT WIEEIP-KIZP, SLEOVT GIVM RFI FNU PTDTZ KTTP
EIZT AFNP N ELVT GZIE AFT FIJST RFTZT AFTB RTZT KIZP JPALV AFT UNB
SIET VIZU WNET ZIJPU AI ANMT AFTE IGG AI RNZ. BIJZ GVNQ LS "PI AFLS
LS PIA WZBOAI EB UTNZ", LP VIRTZWNST, RLAF JPUTZSWIZTS LPSATNU IG
SONWTS, SJZZIJPUTU KB AFT JSJNV "GVNQ" ANQ NPU WJZVB KZNWTS. TPHIB.

3.得到有用信息和flag

BROKEN MEN ARE MORE DESERVING OF OUR PITY, THOUGH THEY MAY BE JUST AS DANGEROUS. ALMOST ALL ARE COMMON-BORN, SIMPLE FOLK WHO HAD NEVER BEEN MORE THAN A MILE FROM THE HOUSE WHERE THEY WERE BORN UNTIL THE DAY SOME LORD CAME ROUND TO TAKE THEM OFF TO WAR. YOUR FLAG IS "NO THIS IS NOT CRYPTO MY DEAR", IN LOWERCASE, WITH UNDERSCORES INSTEAD OF SPACES, SURROUNDED BY THE USUAL "FLAG" TAG AND CURLY BRACES. ENJOY.
破碎的人更值得我们同情，尽管他们可能同样危险。几乎所有人都是普通的普通人，他们从未离他们出生的房子超过一英里，直到有一天某位领主来将他们带去战争。您的旗帜是“不，亲爱的，这不是加密货币”，小写，下划线代替空格，周围是通常的“旗帜”标签和花括号。请享用。

FLAG

no_this_is_not_crypto_my_dear

作者：damedane-qiuqiu