TUCTF 2022 - A Sheep Jumps Over Fence
A Sheep Jumps Over Fence is a crypto challenge that was part of the 2022 TUCTF. We have to decrypt
0x56455a7059574e7459584a685a576c756557646f59565637633364765a57647664\
474e305a48427965584e4464476c6c62584e6c6257463165574e3059574e7a56\
47687a6247567a5a6d527a636d46796233427366513d3d
without knowing anything about the encryption method used.
Solution
In order to solve this challenge, we used CyberChef.
The string starts with 0x
, which means it could be a hexadecimal string. We can convert it by using the From Hex
recipe: step one.
Output:
VEZpYWNtYXJhZWlueWdoYVV7c3dvZWdvdGN0ZHByeXNDdGllbXNlbWF1eWN0YWNzVGhzbGV\
zZmRzcmFyb3BsfQ==
It ends with ==
, which means it could be a base64 string. We can convert it by using the From Base64
recipe: step two.
Output:
TFiacmaraeinyghaU{swoegotctdprysCtiemsemauyctacsThslesfdsraropl}
Wow, this looks like it already has all flag-characters.
Considering the challenge title A Sheep Jumps Over Fence
we could try the some Fence
cipher like the Caesar Box Cipher
. After guessing the Box Height
(16) we got the flag: step three.
Flag
The flag is “TUCTF{thisisawelcomemessagefromdatasecurityandcryptographyclass}”.