const_xor_key = [121, 84, 0, 56, 68, 247, 12, 73, 235, 148, 10, 165, 203, 16, 33, 110, 47, 25, 18, 24, 65, 179, 174, 19,
130, 0, 239, 9, 121, 251, 5, 107, 45, 153, 74, 43, 50, 52, 205, 77, 86, 237, 140, 233, 234, 50, 28, 82,
62, 15, 216, 206, 62, 151, 183, 163, 99, 115, 216, 0, 211, 207, 197, 135, 65, 182, 119]
swap_code = bytes.fromhex('83ec4ca10030400033c48944244853555657bb18344000')
main_code = bytes.fromhex('6810214000FF15DC3F40006800384000FF15D83F40006820214000FF15DC3F400068'
'18344000FF15D83F400068D03F4000FF15D43F400083C414FF15A020400033C0C3')
def xor_sum(_s):
res = 0
for c in _s:
res ^= c
return res
def swap_bits(_b, _x, rev=False):
_x &= 7
if rev:
hi = _b >> _x
lo = _b << (8 - _x)
else:
lo = _b >> (8 - _x)
hi = _b << _x
hi &= 0xff
lo &= 0xff
return hi | lo
user = b'KCTF'
u_index = (xor_sum(user) & 0xf) * 2
goal = list(main_code[:u_index] + b'KCTF-2024-CRACK-SUCCESS' + main_code[u_index + 23:])
for i in range(u_index, u_index + 23):
goal[i] = swap_bits(goal[i], swap_code[i - u_index], True)
for i in range(67):
goal[i] ^= 0xc3 ^ const_xor_key[i]
goal[66] = xor_sum(goal[:66]) ^ 203 ^ 0xc3
print("Serial:", bytes(goal).hex())
