一次简单的CTF

工具脚本

  • 凯撒密码
    1
    2
    3
    4
    5
    6
    7
    def caesar_offset(s, i):
        if not -25 <= i <= 25:
            return False
        origin = map(lambda c: chr((ord(c) - 65 + i) % 26 + 65) if 65 <= ord(c) <= 90
        else chr((ord(c) - 97 + i) % 26 + 97) if 97 <= ord(c) <= 122
        else c, s)
        return ''.join(origin)
  • base64
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    def b64de(s):
        print(" B64 start ".center(64, '-'))
        r = ""
        deb64 = base64.b64decode(s)
        try:
            print("try:utf-8 decode")
            print(deb64.decode("utf-8"))
        except:
            print("\nCantdecode UTF-8")
        print()
        for i in deb64:
            print(('%02x' % i).upper(), end=' ')
        print()
        print("try:chr decode")

        for i in deb64:
            print(chr(i), end='')
            r += chr(i)
        print()
        print(" B64 stop ".center(64, '-'))
        return r
  • 二进制字符串转ASCII
    1
    2
    3
    4
    5
    6
    7
    8
    def binToASCII(bin_str):
        bin_str = bin_str.replace('\n', '').replace(' ', '')
        r = ""
        print(len(bin_str))
        for i in range(len(bin_str) // 8):
            byte_str = bin_str[i * 8:i * 8 + 8]
            r += chr(int(byte_str, 2)) if byte_str != '00000000' else ''
        return r
  • 黑白图转二进制字符串
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    def imgToBin(path, mode='B0W1'):
        im = Image.open(path)
        im = im.convert("1")

        bin_str = ""
        black, white = ('0', '1') if mode == 'B0W1' else ('1', '0') if mode == 'B1W0' else ('0', '0')
        for j in range(im.size[1]):
            for i in range(im.size[0]):
                if im.getpixel((i, j)) >= 128:
                    bin_str += white
                else:
                    bin_str += black
        return bin_str

源

源
+
图片隐写术
=

1
2
3
hJBCY1PhUCHoSBj6EpFoiJrbSMFuEL5YWAu0VCnMEqdjjfqcCIvbZYyqhYE2Qq0QIqO5SW==

ks6w!

ks6w
凯撒+6

1
bDVWS1JbOWBiMVd6YjZicDlvMGZoYF5SQUo0PWhGYkxddzkwWCpvTSskbSY2Kk0KCkI5MQ==

base64 -d 解出

1
2
3
l5VKR[9`b1Wzb6bp9o0fh`^RAJ4=hFbL]w90X*oM+$m&6*M

B91

base91.decode(s)解出

1
https://od.uuu.gay/33.7z  b1Wzb6bp9o0f

下载到文件33.7z 密码b1Wzb6bp9o0f
解压出33.wav

Rot36 decode 出二维码

扫得

1
l5VKR[9`b1Wzb6bp9o0fh`^R<1}$_YmL/1W<vnhdY%E?hF

base91.decode(s)解出

1
https://od.uuu.gay/321.7z  Sc3885s38z

下载到文件321.7z 密码Sc3885s38z
解压出321.png

扫得

1
kwwsv://bkmi.ff/w/Vf3885v38c

凯撒+3

1
https://yhjf.cc/t/Sc3885s38z
一次简单的CTF
https://siltal.github.io/2022/01/21/一次简单的CTF/
Author
Siltal
Posted on
January 21, 2022
Licensed under