[DDCTF2018](╯°□°）╯︵ ┻━┻

[DDCTF2018](╯°□°）╯︵ ┻━┻

Title address : https://buuoj.cn/challenges#[DDCTF2018](%E2%95%AF%C2%B0%E2%96%A1%C2%B0%EF%BC%89%E2%95%AF%EF%B8%B5%20%E2%94%BB%E2%94%81%E2%94%BB

Unzip and check txt, It looks strange , Group the following data , In groups of two

d4e8e1f4a0f7e1f3a0e6e1f3f4a1a0d4e8e5a0e6ece1e7a0e9f3baa0c4c4c3d4c6fbb9b2b2e1e2b9b9b7b4e1b4b7e3e4b3b2b2e3e6b4b3e2b5b0b6b1b0e6e1e5e1b5fd

d4 e8 e1 f4 a0 f7 e1 f3 a0 e6 e1 f3 f4 a1 a0 d4 e8 e5 a0 e6 ec e1 e7 a0 e9 f3 ba a0 c4 c4 c3 d4 c6 fb b9 b2 b2 e1 e2 b9 b9 b7 b4 e1 b4 b7 e3 e4 b3 b2 b2 e3 e6 b4 b3 e2 b5 b0 b6 b1 b0 e6 e1 e5 e1 b5 fd

Turn into 10 It is found that these numbers exceed ascii Code printable range , Decrement the decimal numbers

a = "d4e8e1f4a0f7e1f3a0e6e1f3f4a1a0d4e8e5a0e6ece1e7a0e9f3baa0c4c4c3d4c6fbb9b2b2e1e2b9b9b7b4e1b4b7e3e4b3b2b2e3e6b4b3e2b5b0b6b1b0e6e1e5e1b5fd"
for j in range(1,130):
    for i in range(0,len(a),2):
        data = (int(a[i:i+2],16))
        try:
            print(chr(data-j),end='')
        except:
            pass

Find out flag

Simplified script , Direct pair 10 Decimal number subtraction 128

a = "d4e8e1f4a0f7e1f3a0e6e1f3f4a1a0d4e8e5a0e6ece1e7a0e9f3baa0c4c4c3d4c6fbb9b2b2e1e2b9b9b7b4e1b4b7e3e4b3b2b2e3e6b4b3e2b5b0b6b1b0e6e1e5e1b5fd"
for i in range(0,len(a),2):
    data = int(a[i:i+2],16) - 128
    print(chr(data),end='')