leaky_crypto QA/QC

[pyrodie18]

• Name: leaky_crypto
• Designer: Troy
• Category: Crypto
• Description: We encrypted the flag with AES-ECB and a secret key and got the following: b7695884638a2d5551c0a1ed35142c939a60791aba95dbaedd2994d677907602a0779b858857a3a3d04304fcde225ce7228993a1a0cd57ab37425fc7b32d4ca775053f0b39dccb6e9eb88ae40ec8aa9f

Unfortunately we lost the key. On the bright side though we did encrypt a bunch of other test flags with the same key before we lost it. Can you help us out?

• Required Resources: codes.txt
• Flag: acsc18{encryption_is_great_but_only_if_it_doesnt_leak_like_my_old_pipes}

When you are done with the QA/QC, please enter a comment stating so and how you would rate the difficulty . If you see any issues please note them in the comment as well.

• [x] Dockerized
• [ ] Tested
• [ ] Loaded to Game Engine
• [ ] Loaded to Environment
• [x] Tested in Environment

Difficulty key

0 - No background 3 - JCAC (Basic) 6 - Scripting (Senior) 9 - Reverse Engineer (Master)

Instructions: For each new challenge complete the above information. Assign the "QA/QC" and "Load Game Engine", labels to all challenges. If required add "Dockerize" and "Challenge Server" for challenges that need to be dockerized or will have to be hosted on the challenge server

[mhuiz]

QC'ed Difficulty: 5 I'm not sure I could have done this without the key, but it could be because I have never done manual AES decryption before, but the codes.txt file seems to have some critical typo errors. acsc18{ivan_wentn_is_great_but_one_look_under_the_hood} : 3b4bd5b6f194cbbb1495a469d611c9a49a60791aba95dbaedd2994d67790760201582d16b6eba3152076c4c308a01e8fba99ded4683389cbf0253ba93b5908f5 -Should this read, "acsc18{ivans_winton..."? That would make this line up better. acsc18{this_is_tnly_if_it_doesnt_look_like_the_plain_text} : ef002b7295f186d228eed3d9e0a9e922a0779b858857a3a3d04304fcde225ce7078b383949d500ba73f9dd9258801c4137494c3df395c4500b2b36c7bb2ec8bd -Should this read, "...this_is_only..."? acsc18{one_two_three_four_i_declare_a_thumb_wardd_pipes} : 65a67d9d1b3a3a207813fe56cf87374ee07b5bd56069eb93f67f96cfecaffed00cd2d8374a493fd451d6e9129db46c3975053f0b39dccb6e9eb88ae40ec8aa9f -Should this read, "...thumb_war_pipes}"

[pyrodie18]

@mhuiz Just checked and there's not typo's there. The misspelled words fall outside of the portion of the flag that that line represents. In all of those cases, they were misspelled to allow the block boundaries to line up where they need to.

[mhuiz]

Yep, I gave it a shot. Back to the books on AES.

[ghost]

50 points