BUUCTF--findit

测试文件：https://buuoj.cn/files/7b8602971727c6c82ec0d360d5cad2c0/6a428ff2-25d7-403c-b28e-3f980a10a5a2.apk?token=eyJ0ZWFtX2lkIjpudWxsLCJ1c2VyX2lkIjoxOTAzLCJmaWxlX2lkIjoyMTV9.XYmTqw.OyIU1nla76d5HdmzUbwmtT9twOg

1.APKIDE打开

找到一组十六进制数

转换为字符串之后为

pvkq{m164675262033l4m49lnp7p9mnk28k75}

2.凯撒解密

model = "abcdefghijklmnopqrstuvwxyz"

str1 = "pvkq{m164675262033l4m49lnp7p9mnk28k75}"

for i in range(1,27):
    print("key=%d"%i, end='\n')
    for s in str1:
        if s.isalpha():
            n = model.find(s)
            s = model[n-i]
        print(s, end='')
    print('\n')

key=1
oujp{l164675262033k4l49kmo7o9lmj28j75}

key=2
ntio{k164675262033j4k49jln7n9kli28i75}

key=3
mshn{j164675262033i4j49ikm7m9jkh28h75}

key=4
lrgm{i164675262033h4i49hjl7l9ijg28g75}

key=5
kqfl{h164675262033g4h49gik7k9hif28f75}

key=6
jpek{g164675262033f4g49fhj7j9ghe28e75}

key=7
iodj{f164675262033e4f49egi7i9fgd28d75}

key=8
hnci{e164675262033d4e49dfh7h9efc28c75}

key=9
gmbh{d164675262033c4d49ceg7g9deb28b75}

key=10
flag{c164675262033b4c49bdf7f9cda28a75}

key=11
ekzf{b164675262033a4b49ace7e9bcz28z75}

key=12
djye{a164675262033z4a49zbd7d9aby28y75}

key=13
cixd{z164675262033y4z49yac7c9zax28x75}

key=14
bhwc{y164675262033x4y49xzb7b9yzw28w75}

key=15
agvb{x164675262033w4x49wya7a9xyv28v75}

key=16
zfua{w164675262033v4w49vxz7z9wxu28u75}

key=17
yetz{v164675262033u4v49uwy7y9vwt28t75}

key=18
xdsy{u164675262033t4u49tvx7x9uvs28s75}

key=19
wcrx{t164675262033s4t49suw7w9tur28r75}

key=20
vbqw{s164675262033r4s49rtv7v9stq28q75}

key=21
uapv{r164675262033q4r49qsu7u9rsp28p75}

key=22
tzou{q164675262033p4q49prt7t9qro28o75}

key=23
synt{p164675262033o4p49oqs7s9pqn28n75}

key=24
rxms{o164675262033n4o49npr7r9opm28m75}

key=25
qwlr{n164675262033m4n49moq7q9nol28l75}

key=26
pvkq{m164675262033l4m49lnp7p9mnk28k75}

3.get flag！

flag{c164675262033b4c49bdf7f9cda28a75}