solve_sms.py

SBOX = [0xb9, 0xb3, 0x49, 0x94, 0xf9, 0x3, 0xd0, 0xfc, 0x67, 0xa3, 0x72, 0xb5,
	 0x45, 0x82, 0x54, 0x93, 0x5b, 0x88, 0x5c, 0xe0, 0x96, 0x41, 0xc7, 0xa,
	 0xdb, 0x7f, 0x77, 0x29, 0x9, 0xb, 0x8d, 0x80, 0x2d, 0xaf, 0xe1, 0x4a,
	 0x38, 0x73, 0x3a, 0x6a, 0xf2, 0xb6, 0xdc, 0xbd, 0x79, 0x2a, 0xcb, 0x55,
	 0x10, 0x61, 0x63, 0x68, 0x13, 0x95, 0x9f, 0x1c, 0x4f, 0x35, 0x5f, 0xae,
	 0x37, 0xb8, 0xfe, 0xea, 0x7a, 0x4b, 0xc3, 0xe8, 0xc6, 0x44, 0x60, 0xb2,
	 0x5a, 0x2e, 0xeb, 0x47, 0x1e, 0x4d, 0x9a, 0x98, 0x36, 0xe7, 0x48, 0x3e,
	 0x42, 0x6b, 0xa1, 0x65, 0xb1, 0x57, 0x6c, 0x4, 0xff, 0xfd, 0x34, 0x40,
	 0x31, 0x8c, 0xbe, 0xda, 0x2c, 0x1b, 0x7c, 0x64, 0x3f, 0xd1, 0xc9, 0x9b,
	 0x25, 0x87, 0xaa, 0xd, 0x15, 0x1f, 0xce, 0x30, 0xfb, 0xd5, 0xef, 0xbb,
	 0x24, 0x28, 0x90, 0x2f, 0x85, 0xc5, 0x4c, 0x97, 0xa8, 0x16, 0x43, 0xac,
	 0x74, 0xc0, 0x8b, 0xc4, 0xe9, 0x7e, 0xf5, 0xd2, 0xab, 0x12, 0xd8, 0xdd,
	 0xa9, 0xad, 0x21, 0xd7, 0xed, 0x1, 0x32, 0xbf, 0xa6, 0x8a, 0xe3, 0x6f,
	 0xde, 0x84, 0xc8, 0x6d, 0x92, 0x99, 0x51, 0x39, 0xe5, 0x46, 0x9c, 0xf0,
	 0x0, 0x8e, 0xbc, 0xa2, 0x22, 0x9d, 0xc2, 0xfa, 0xb0, 0x33, 0x56, 0xec,
	 0xdf, 0x89, 0x52, 0x8, 0x62, 0x7, 0x59, 0xb7, 0xe4, 0x14, 0x9e, 0x70,
	 0xd9, 0xe, 0x3d, 0x26, 0x1d, 0x66, 0x71, 0xe2, 0x5, 0x6e, 0x5d, 0xf6,
	 0x18, 0xf, 0xcf, 0xd6, 0xe6, 0xba, 0x1a, 0x78, 0xf8, 0x76, 0xd3, 0x50,
	 0xf7, 0x58, 0x17, 0x91, 0x11, 0x86, 0xf1, 0xa4, 0x19, 0x4e, 0x6, 0xa0,
	 0xca, 0xa5, 0xf3, 0xee, 0xcd, 0x53, 0x5e, 0xa7, 0xc, 0xb4, 0x2, 0xc1,
	 0x3b, 0x27, 0x69, 0x7d, 0x8f, 0xcc, 0x20, 0x7b, 0x81, 0x2b, 0x83, 0x23,
	 0xd4, 0x3c, 0xf4, 0x75]

def sub(state):
	return [SBOX[x] for x in state]
def mix(block, state):
	for i in range(8):
		state[i] ^= block[7 - i] & 0x1f
		state[i] ^= block[i] & 0xe0
	return state
def shift(state):
	t = 0
	for s in state:
		t ^= s
	u = state[0]
	for i in range(7):
		state[i] ^= t ^ state[i] ^ state[i+1]
	state[7] ^= t ^ state[7] ^ u
	return state

def hash(data):
	assert len(data) % 8 == 0
	state = [2**i-1 for i in range(1, 9)]
	for i in range(0, len(data), 8):
		block = data[i: i+8]
		state = sub(state)
		state = mix(block, state)
		state = shift(state)
	state = sub(state)
	return bytes(state).hex()

###############################################	
def sub_inv(state):
	return [SBOX.index(x) for x in state]

def single_mix(a,b,p,q):
	p^= a & 0x1f
	p^= b & 0xe0
	return p==q
def mix_inv(state,target_state):
	block=[0]*8
	for i in range(4):
		for a in range(256):
			for b in range(256):
				if single_mix(a,b,state[i],target_state[i])==True:
					if single_mix(b,a,state[7-i],target_state[7-i])==True:
						block[i]=b
						block[7-i]=a
	return bytes(block)

def find_input1():
	target=[0,0,0,0,0,0,0,0]
	s=[2**i-1 for i in range(1, 9)]
	s=sub(s)	
	state=sub_inv(target)
	block=mix_inv(state,s)
	return block.hex()
def find_input2():
	target=[0,0,0,0,0,0,0,0]
	state=sub_inv(target)
	block=mix_inv(state,target)
	return (bytes.fromhex(find_input1())+block).hex()
	
print(f"input 1: {find_input1()}")
print(f"input 2: {find_input2()}")