sn长度32, 大写16进制字符
分别验证前半段和后半段
前半段穷举范围为 8!
后半段穷举范围为 8*256
所以把sub_401580提取出来穷举即可
.text:004013E0 cmp ecx, 20h ; ' '
.text:004013E3 jnz short loc_401428
.text:004013E5 lea edx, [esp+38h+String]
.text:004013E9 push ecx
.text:004013EA push edx
.text:004013EB push offset g_code_bin
.text:004013F0 mov ecx, ebx
.text:004013F2 call hex2bin
.text:004013F7 cmp eax, 10h
.text:004013FA jnz short loc_401428
.text:004013FC mov ecx, dword ptr g_code_bin+4
.text:00401402 mov eax, dword ptr g_code_bin
.text:00401407 mov dword ptr g_ary+4, ecx
.text:0040140D push (offset g_code_bin+8)
.text:00401412 mov ecx, ebx
.text:00401414 mov dword ptr g_ary, eax
.text:00401419 call sub_401580
pypy3 test.py
import itertools
def swap(b):
return ((b & 0x0F) << 4) | (b >> 4)
def b2h(buf):
o = bytearray(buf)
for i, b in enumerate(o):
o[i] = swap(b)
return o.hex().upper()
def h2b(buf):
o = bytearray.fromhex(buf)
for i, b in enumerate(o):
o[i] = swap(b)
return o
def test():
code1 = bytearray(8)
code2 = bytearray(8)
# 00404000
ary_init = bytes([
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA2, 0x9B, 0xF4, 0xDF, 0xAC, 0x7C, 0xA1, 0xC6,
0x16, 0xD0, 0x0F, 0xDD, 0xDC, 0x73, 0xC5, 0x6B, 0xD1, 0x96, 0x47, 0xC2, 0x26, 0x67, 0x4E, 0x41,
0x82, 0x20, 0x56, 0x9A, 0x6E, 0x33, 0x92, 0x88, 0x29, 0xB5, 0xB4, 0x71, 0xA9, 0xCE, 0xC3, 0x34,
0x50, 0x59, 0xBF, 0x2D, 0x57, 0x22, 0xA6, 0x30, 0x04, 0xB2, 0xCD, 0x36, 0xD5, 0x68, 0x4D, 0x5B,
0x45, 0x9E, 0x85, 0xCF, 0x9D, 0xCC, 0x61, 0x78, 0x32, 0x76, 0x31, 0xE3, 0x80, 0xAD, 0x39, 0x4F,
0xFA, 0x72, 0x83, 0x4C, 0x86, 0x60, 0xB7, 0xD7, 0x63, 0x0C, 0x44, 0x35, 0xB3, 0x7B, 0x19, 0xD4,
0x69, 0x08, 0x0B, 0x1F, 0x3D, 0x11, 0x79, 0xD3, 0xEE, 0x93, 0x42, 0xDE, 0x23, 0x3B, 0x5D, 0x8D,
0xA5, 0x77, 0x5F, 0x58, 0xDB, 0x97, 0xF6, 0x7A, 0x18, 0x52, 0x15, 0x74, 0x25, 0x62, 0x2C, 0x05,
0xE8, 0x0D, 0x98, 0x2A, 0x43, 0xE2, 0xEF, 0x48, 0x87, 0x49, 0x1C, 0xCA, 0x2B, 0xA7, 0x8A, 0x09,
0x81, 0xE7, 0x53, 0xAA, 0xFF, 0x6F, 0x8E, 0x91, 0xF1, 0xF0, 0xA4, 0x46, 0x3A, 0x7D, 0x54, 0xEB,
0x2F, 0xC1, 0xC0, 0x0E, 0xBD, 0xE1, 0x6C, 0x64, 0xBE, 0xE4, 0x02, 0x3C, 0x5A, 0xA8, 0x9F, 0x37,
0xAF, 0xA0, 0x13, 0xED, 0x1B, 0xEC, 0x8B, 0x3E, 0x7E, 0x27, 0x99, 0x75, 0xAB, 0xFE, 0xD9, 0x3F,
0xF3, 0xEA, 0x70, 0xF7, 0x95, 0xBA, 0x1D, 0x40, 0xB0, 0xF9, 0xE5, 0xF8, 0x06, 0xBC, 0xB6, 0x03,
0xC9, 0x10, 0x9C, 0x2E, 0x89, 0x5C, 0x7F, 0xB1, 0x1A, 0xD6, 0x90, 0xAE, 0xDA, 0xE6, 0x5E, 0xB9,
0x84, 0xE9, 0x55, 0xBB, 0xC7, 0x0A, 0xE0, 0x66, 0xF2, 0xD8, 0xCB, 0x00, 0x12, 0xB8, 0x17, 0x94,
0x6A, 0x4A, 0x01, 0x24, 0x14, 0x51, 0x07, 0x65, 0x21, 0xC8, 0x38, 0xFD, 0x8F, 0xC4, 0xF5, 0xFC,
])
# first part
missing_set = set(ary_init[8:]).symmetric_difference(range(256))
for missing in itertools.permutations(missing_set, 8):
ary = bytearray(ary_init)
ary[0:8] = bytes(missing)
# 00404420
ary2 = bytearray(256*256)
# 00404220
ary3 = bytearray(256*2)
for k in range(256):
ary3[0] = ary[k]
ary3[1] = (k + 1) & 0xFF
idx = 0
# 00404100: 2 + 4 + 8 + 0x10 + 0x20 + 0x40 + 0x80
for i in range(254):
ary3[2 + 2 * i] = ary[ary3[i]]
ary3[3 + 2 * i] = (ary3[i] + 1) & 0xFF
for i in range(254, 510):
ary2[k * 256 + ary3[i]] += 1
ary2[k * 256 + ary3[i]] &= 0xFF
v0 = 0
v1 = 0
v2 = 0
v3 = 0
for i in range(256):
if ary2[i * 256 + 0x00] != 0:
v0 += 1
v0 &= 0xFF
if ary2[i * 256 + 0x0E] != 0:
v1 += 1
v1 &= 0xFF
if ary2[i * 256 + 0x28] != 0:
v2 += 1
v2 &= 0xFF
if ary2[i * 256 + 0x4F] != 0:
v3 += 1
v3 &= 0xFF
if v0 == 0xA9 and v1 == 0xAC and v2 == 0xA7 and v3 > 0xC8:
code1[:] = bytes(missing)
# print(b2h(code1))
break
# second part
ary = bytearray(ary_init)
ary[0:8] = code1
for k in range(256):
i = k
# rotate
v = ary[i]
while ary[i] != k:
ary[i], i = ary[ary[i]], ary[i]
ary[i] = v
expected = b'GoodJob~'
for k in range(8):
for code in range(256):
bs = code
v = ary[k]
for j in range(8):
if ((bs >> j) & 1) != 0:
v += 1
v &= 0xFF
else:
v = ary[v]
if k in [0, 7]:
v -= 1
if v == expected[k]:
code2[k] = code
break
# print(b2h(code2))
print(b2h(code1 + code2))
return
test()
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最后于 2021-11-17 10:18
被风间仁编辑
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