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}”.