Binary level C200
You and your team are close to hacking a very complicated CBC
encryption algorithm. The missing piece of the puzzle is finding a key
which has a special property: a key which only has groups of 2
identical characters. For example, “00:bb:44:22:11:ff:dd” is such a
key, where “12:42:de:ff:aa:cc:34″ is not. You and your team are
searching for the “first” secret key with this property, meaning the
secret key with the lowest possible number of iterations.
Hint: you can solve this level by only changing 1 byte! Enter your
answer using the following format: “00:bb:44:22:11:ff:dd” (without the
quotes).
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I thing the key is ee:88:00:88:77:00:99:dd.
I’m making an instruction to explain how I got to this point …
0: ed 90 de 9a 7f 79 8d dd
1: d9 b2 00 86 77 00 88 00
2: cd d4 de 92 7f 79 8d dd
3: ee f6 00 8e 77 00 88 00
4: d8 8a de 8a 7f 79 8d dd
5: ce 8c 00 96 77 00 88 00
6: ed 8e de 82 7f 79 8d dd
7: d9 b0 00 9e 77 00 88 00
8: cd d2 de ba 7f 79 8d dd
9: ee f4 00 88 77 00 88 00
10: d8 88 de 90 7f 79 8d dd
11: ce 8a 00 88 77 00 88 00
12: ed 8c de 90 7f 79 8d dd
13: d9 8e 00 88 77 00 88 00
14: cd b0 de 90 7f 79 8d dd
15: cd b0 de 90 7f 79 8d dd
ee:88:00:88:77:00:99:dd