攻防世界crypto部分ecb,_it’s_easy_as_123的writeup

Somebody leaked a still from the upcoming Happy Feet Three movie, which will be released in 4K, but Warner Bros. was smart enough to encrypt it. But those idiots used a black and white bmp format, and that wasn't their biggest mistake. Show 'em who's boss and get the flag.

创建3840×2160的分辨率，16色深的bm的头，替换掉原来的头即可，

分析详见：https://github.com/ctfs/write-ups-2014/tree/master/tinyctf-2014/ecb-its-easy-as-123

即将前面的字节码

53 61 6c 74 65 64 5f 5f  ab 31 b5 e5 ca 3d b9 4d
f4 09 1a a5 df 88 b7 2c  0e bd 8a 73 98 15 ba 69
a2 24 3e 09 94 cb 79 1e  ea a1 ad 33 c8 17 66 63
78 98 23 0b f0 af 20 38  f1 aa 0b f4 69 1c ec cf
fc d8 8e 3d 45 2a 99 b0  53 6b 50 0d 8a 3d c4 b7
62 9c 6a 54 f0 59 20 13  22 4f b6 e2 b6 aa 0a 8b
5e 21 1a 9d cf 8c a2 f6  45 80 cb 9b b7 37 da 7f
73 50 88 cb df 63 ee 22  d4 24 b3 b9 f4 24 ad 40

替换成

424d 7648 3f00 0000 0000 7600 0000 2800
0000 000f 0000 7008 0000 0100 0400 0000
0000 0048 3f00 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 8000 0080
0000 0080 8000 8000 0000 8000 8000 8080
0000 8080 8000 c0c0 c000 0000 ff00 00ff
0000 00ff ff00 ff00 0000 ff00 ff00 ffff
0000 ffff ff00 ffff ffff ffff ffff ffff

即可看见：

flag就是

flag{no_penguin_here}