fORtran - smileyCTF 2025

Fortranのバイナリが与えられる

code: python

arr1 = [

0x000000bf, 0x000000f3, 0x0000003b, 0x00000025,

0x000000b3, 0x0000002f, 0x00000097, 0x0000001a,

0x000000d9, 0x000000bf, 0x000000aa, 0x000000a2,

0x000000a6, 0x00000055, 0x000000c4, 0x000000ca,

0x00000015, 0x00000090, 0x00000093, 0x00000051,

0x0000008b, 0x00000034, 0x00000041, 0x0000006e,

0x0000000b, 0x00000024, 0x000000f1, 0x000000bb

]

def dec(v1):

v2 = []

for i in range(len(arr1)):

v1 = ((4919 * v1) ^ 0xdeadbeef) & 0xffffffff

return bytes(v2)

for i in range(256):

decoded = dec(i)

if b'.;,;.' in decoded:

print(decoded)

break