[*CTF2019]babyflash

用JPEXS反编译flash.swf得到441张黑白图片和1个mp3文件

软件下载地址：https://github.com/jindrapetrik/jpexs-decompiler/releases

右键导出图片

图片很规律，张数刚好是441=21*21，按照图片顺序，黑为1白为0，拼凑出0-1序列

图像处理脚本——识别1和0：

from PIL import Image

def aaa(s):

    image = Image.open("frames/"+str(i)+".png")

    a,b,c,d = image.getpixel((50,50))

    return a

s=''

for i in range(1,442):

    if aaa(i)==0:

        s+=''

    else:

        s+=''

print (s)

输出：

111111100110001111111100000100111001000001101110101011001011101101110100100101011101101110100101101011101100000100110001000001111111101010101111111000000001010100000000111011111011111000100110110011011101111011101101111001101111011010010001100000000011111010100000100011000000000001011100110011111111101011100110101100000101101000100010101110101011011000001101110100101101110000101110101101110110001100000101011100010010111111101101100001011

尝试一下拼一起

图片处理脚本——拼接图片：

from PIL import Image

length = 21

img = Image.new('RGB', (length*5, length*5))

#黑点为1白点为0

data = ""

for x in range(length):

    for y in range(length):

        if data[x*length+y] == '':

            for xx in range(x*5, x*5+5):

                for yy in range(y*5, y*5+5):

                    img.putpixel([xx, yy], (0,0,0))

        else:

            for xx in range(x*5, x*5+5):

                for yy in range(y*5, y*5+5):

                    img.putpixel([xx, yy], (255,255,255))

img.save('out.png')

输出：

得到前半个flag

*ctf{half_flag_&

再导出mp3文件，这个是常见套路频谱隐写，得到后半段flag

&_the_rest}

参考：https://zhuanlan.zhihu.com/p/64252028

巴特西

[*CTF2019]babyflash

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