2020年「羊城杯」网络安全大赛 Re部分 WriteUp
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2022-05-14 08:05:03
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Re
login
使用PyInstaller Extractor v2.0把exe进行解包, 在解包指令中发现Python version: 36, 切换到python3.6环境中
可以看见入口文件为login.pyc, 使用uncompyle6 login.pyc解析pyc文件看到一堆数字, 嗯, 又是方程组, 上z3
from z3 import *
a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14 = Ints("a1 a2 a3 a4 a5 a6 a7 a8 a9 a10 a11 a12 a13 a14")
x = Solver()
x.add(a1 * 88 + a2 * 67 + a3 * 65 - a4 * 5 + a5 * 43 + a6 * 89 + a7 * 25 + a8 * 13 - a9 * 36 + a10 * 15 + a11 * 11 + a12 * 47 - a13 * 60 + a14 * 29 == 22748)
x.add(a1 * 89 + a2 * 7 + a3 * 12 - a4 * 25 + a5 * 41 + a6 * 23 + a7 * 20 - a8 * 66 + a9 * 31 + a10 * 8 + a11 * 2 - a12 * 41 - a13 * 39 + a14 * 17 == 7258)
x.add(a1 * 28 + a2 * 35 + a3 * 16 - a4 * 65 + a5 * 53 + a6 * 39 + a7 * 27 + a8 * 15 - a9 * 33 + a10 * 13 + a11 * 101 + a12 * 90 - a13 * 34 + a14 * 23 == 26190)
x.add(a1 * 23 + a2 * 34 + a3 * 35 - a4 * 59 + a5 * 49 + a6 * 81 + a7 * 25 + a8 * 128 - a9 * 32 + a10 * 75 + a11 * 81 + a12 * 47 - a13 * 60 + a14 * 29 == 37136)
x.add(a1 * 38 + a2 * 97 + a3 * 35 - a4 * 52 + a5 * 42 + a6 * 79 + a7 * 90 + a8 * 23 - a9 * 36 + a10 * 57 + a11 * 81 + a12 * 42 - a13 * 62 - a14 * 11 == 27915)
x.add(a1 * 22 + a2 * 27 + a3 * 35 - a4 * 45 + a5 * 47 + a6 * 49 + a7 * 29 + a8 * 18 - a9 * 26 + a10 * 35 + a11 * 41 + a12 * 40 - a13 * 61 + a14 * 28 == 17298)
x.add(a1 * 12 + a2 * 45 + a3 * 35 - a4 * 9 - a5 * 42 + a6 * 86 + a7 * 23 + a8 * 85 - a9 * 47 + a10 * 34 + a11 * 76 + a12 * 43 - a13 * 44 + a14 * 65 == 19875)
x.add(a1 * 79 + a2 * 62 + a3 * 35 - a4 * 85 + a5 * 33 + a6 * 79 + a7 * 86 + a8 * 14 - a9 * 30 + a10 * 25 + a11 * 11 + a12 * 57 - a13 * 50 - a14 * 9 == 22784)
x.add(a1 * 8 + a2 * 6 + a3 * 64 - a4 * 85 + a5 * 73 + a6 * 29 + a7 * 2 + a8 * 23 - a9 * 36 + a10 * 5 + a11 * 2 + a12 * 47 - a13 * 64 + a14 * 27 == 9710)
x.add(a1 * 67 - a2 * 68 + a3 * 68 - a4 * 51 - a5 * 43 + a6 * 81 + a7 * 22 - a8 * 12 - a9 * 38 + a10 * 75 + a11 * 41 + a12 * 27 - a13 * 52 + a14 * 31 == 13376)
x.add(a1 * 85 + a2 * 63 + a3 * 5 - a4 * 51 + a5 * 44 + a6 * 36 + a7 * 28 + a8 * 15 - a9 * 6 + a10 * 45 + a11 * 31 + a12 * 7 - a13 * 67 + a14 * 78 == 24065)
x.add(a1 * 47 + a2 * 64 + a3 * 66 - a4 * 5 + a5 * 43 + a6 * 112 + a7 * 25 + a8 * 13 - a9 * 35 + a10 * 95 + a11 * 21 + a12 * 43 - a13 * 61 + a14 * 20 == 27687)
x.add(a1 * 89 + a2 * 67 + a3 * 85 - a4 * 25 + a5 * 49 + a6 * 89 + a7 * 23 + a8 * 56 - a9 * 92 + a10 * 14 + a11 * 89 + a12 * 47 - a13 * 61 - a14 * 29 == 29250)
x.add(a1 * 95 + a2 * 34 + a3 * 62 - a4 * 9 - a5 * 43 + a6 * 83 + a7 * 25 + a8 * 12 - a9 * 36 + a10 * 16 + a11 * 51 + a12 * 47 - a13 * 60 - a14 * 24 == 15317)
print(x.check())
print(x.model())
>>> [a2 = 24,
a13 = 88,
a6 = 43,
a9 = 52,
a14 = 33,
a5 = 104,
a12 = 74,
a7 = 28,
a1 = 119,
a10 = 108,
a11 = 88,
a8 = 91,
a4 = 7,
a3 = 10]
按照ord(input1[i]) ^ ord(input1[i + 1])进行异或, 反推回input[85, 95, 71, 48, 55, 95, 116, 104, 51, 95, 107, 51, 121, 33], 转换为字符串
c = [85, 95, 71, 48, 55, 95, 116, 104, 51, 95, 107, 51, 121, 33]
for i in c:
print(chr(i), end="")
>>> U_G07_th3_k3y!
easyre
IDA查看整体逻辑, 发现是flag经过encode_one encode_two encode_three三次编码后变成EmBmP5Pmn7QcPU4gLYKv5QcMmB3PWHcP5YkPq3=cT6QckkPckoRG, 首先怀疑有base64
查看
encode_one, 看到一个变量alphabet, 对应的ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/, 不用怀疑就是base64,
查看encode_two, 看到4个strncpy用法, 分析后可画出此图
查看encode_three, 貌似很复杂的样子, 画出数轴, 分析后画出此图
先还原encode_three, 我突然想到这是一一对应的关系, 把这个关系写出来然后生成一张map就行了
def m(v5):
if v5 <= 64 or v5 > 90:
if v5 <= 96 or v5 > 122:
if v5 <= 47 or v5 > 57:
return chr(v5)
else:
return chr((v5 - 45) % 10 + 48)
else:
return chr((v5 - 94) % 26 + 97)
else:
return chr((v5 - 62) % 26 + 65)
mm = {}
for i in range(33, 127):
raw = i
fin = m(i)
mm[fin] = chr(raw)
data = "EmBmP5Pmn7QcPU4gLYKv5QcMmB3PWHcP5YkPq3=cT6QckkPckoRG"
print(mm)
fin2 = ""
for c in data:
fin2 += mm[c]
print(fin2)
>>> {'!': '!', '"': '"', '#': '#', '$': '$', '%': '%', '&': '&', "'": "'", '(': '(', ')': ')', '*': '*', '+': '+', ',': ',', '-': '-', '.': '.', '/': '/', '3': '0', '4': '1', '5': '2', '6': '3', '7': '4', '8': '5', '9': '6', '0': '7', '1': '8', '2': '9', ':': ':', ';': ';', '<': '<', '=': '=', '>': '>', '?': '?', '@': '@', 'D': 'A', 'E': 'B', 'F': 'C', 'G': 'D', 'H': 'E', 'I': 'F', 'J': 'G', 'K': 'H', 'L': 'I', 'M': 'J', 'N': 'K', 'O': 'L', 'P': 'M', 'Q': 'N', 'R': 'O', 'S': 'P', 'T': 'Q', 'U': 'R', 'V': 'S', 'W': 'T', 'X': 'U', 'Y': 'V', 'Z': 'W', 'A': 'X', 'B': 'Y', 'C': 'Z', '[': '[', '\\': '\\', ']': ']', '^': '^', '_': '_', '`': '`', 'd': 'a', 'e': 'b', 'f': 'c', 'g': 'd', 'h': 'e', 'i': 'f', 'j': 'g', 'k': 'h', 'l': 'i', 'm': 'j', 'n': 'k', 'o': 'l', 'p': 'm', 'q': 'n', 'r': 'o', 's': 'p', 't': 'q', 'u': 'r', 'v': 's', 'w': 't', 'x': 'u', 'y': 'v', 'z': 'w', 'a': 'x', 'b': 'y', 'c': 'z', '{': '{', '|': '|', '}': '}', '~': '~'}
>>> BjYjM2Mjk4NzMR1dIVHs2NzJjY0MTEzM2VhMn0=zQ3NzhhMzhlOD
还原encode_two, 参照画的图对原来的字符串进行还原, 最后base64解码
import base64
data = "BjYjM2Mjk4NzMR1dIVHs2NzJjY0MTEzM2VhMn0=zQ3NzhhMzhlOD"
raw = ["0" for _ in range(38)]
raw[0: 13] = data[13: 26]
raw[13: 26] = data[39: 52]
raw[26: 39] = data[0: 13]
raw[39: 52] = data[26: 39]
print(base64.b64decode("".join(raw).encode()).decode())
>>> GWHT{672cc4778a38e80cb362987341133ea2}
Bytecode
第一次遇到这种题目, Bytecode为python的字节码转换成人类可读的形式, 当smail来读就行, 还原成python脚本
4 0 LOAD_CONST 0 (3)
3 LOAD_CONST 1 (37)
6 LOAD_CONST 2 (72)
9 LOAD_CONST 3 (9)
12 LOAD_CONST 4 (6)
15 LOAD_CONST 5 (132)
18 BUILD_LIST 6
21 STORE_NAME 0 (en)
5 24 LOAD_CONST 6 (101)
27 LOAD_CONST 7 (96)
30 LOAD_CONST 8 (23)
33 LOAD_CONST 9 (68)
36 LOAD_CONST 10 (112)
39 LOAD_CONST 11 (42)
42 LOAD_CONST 12 (107)
45 LOAD_CONST 13 (62)
48 LOAD_CONST 7 (96)
51 LOAD_CONST 14 (53)
54 LOAD_CONST 15 (176)
57 LOAD_CONST 16 (179)
60 LOAD_CONST 17 (98)
63 LOAD_CONST 14 (53)
66 LOAD_CONST 18 (67)
69 LOAD_CONST 19 (29)
72 LOAD_CONST 20 (41)
75 LOAD_CONST 21 (120)
78 LOAD_CONST 22 (60)
81 LOAD_CONST 23 (106)
84 LOAD_CONST 24 (51)
87 LOAD_CONST 6 (101)
90 LOAD_CONST 25 (178)
93 LOAD_CONST 26 (189)
96 LOAD_CONST 6 (101)
99 LOAD_CONST 27 (48)
102 BUILD_LIST 26
105 STORE_NAME 1 (output)
7 108 LOAD_CONST 28 ('welcome to GWHT2020')
111 PRINT_ITEM
112 PRINT_NEWLINE
9 113 LOAD_NAME 2 (raw_input)
116 LOAD_CONST 29 ('please input your flag:')
119 CALL_FUNCTION 1
122 STORE_NAME 3 (flag)
10 125 LOAD_NAME 3 (flag)
128 STORE_NAME 4 (str)
12 131 LOAD_NAME 5 (len)
134 LOAD_NAME 4 (str)
137 CALL_FUNCTION 1
140 STORE_NAME 6 (a)
13 143 LOAD_NAME 6 (a)
146 LOAD_CONST 30 (38)
149 COMPARE_OP 0 (<)
152 POP_JUMP_IF_FALSE 173
14 155 LOAD_CONST 31 ('lenth wrong!')
158 PRINT_ITEM
159 PRINT_NEWLINE
15 160 LOAD_NAME 7 (exit)
163 LOAD_CONST 32 (0)
166 CALL_FUNCTION 1
169 POP_TOP
170 JUMP_FORWARD 0 (to 173)
17 >> 173 LOAD_NAME 8 (ord)
176 LOAD_NAME 4 (str)
179 LOAD_CONST 32 (0)
182 BINARY_SUBSCR
183 CALL_FUNCTION 1
186 LOAD_CONST 33 (2020)
189 BINARY_MULTIPLY
190 LOAD_NAME 8 (ord)
193 LOAD_NAME 4 (str)
196 LOAD_CONST 34 (1)
199 BINARY_SUBSCR
200 CALL_FUNCTION 1
203 BINARY_ADD
204 LOAD_CONST 33 (2020)
207 BINARY_MULTIPLY
208 LOAD_NAME 8 (ord)
211 LOAD_NAME 4 (str)
214 LOAD_CONST 35 (2)
217 BINARY_SUBSCR
218 CALL_FUNCTION 1
221 BINARY_ADD
222 LOAD_CONST 33 (2020)
225 BINARY_MULTIPLY
226 LOAD_NAME 8 (ord)
229 LOAD_NAME 4 (str)
232 LOAD_CONST 0 (3)
235 BINARY_SUBSCR
236 CALL_FUNCTION 1
239 BINARY_ADD
240 LOAD_CONST 33 (2020)
243 BINARY_MULTIPLY
244 LOAD_NAME 8 (ord)
247 LOAD_NAME 4 (str)
250 LOAD_CONST 36 (4)
253 BINARY_SUBSCR
254 CALL_FUNCTION 1
257 BINARY_ADD
258 LOAD_CONST 37 (1182843538814603)
261 COMPARE_OP 2 (==)
264 POP_JUMP_IF_FALSE 275
18 267 LOAD_CONST 38 ('good!continue\xe2\x80\xa6\xe2\x80\xa6')
270 PRINT_ITEM
271 PRINT_NEWLINE
272 JUMP_FORWARD 15 (to 290)
20 >> 275 LOAD_CONST 39 ('bye~')
278 PRINT_ITEM
279 PRINT_NEWLINE
21 280 LOAD_NAME 7 (exit)
283 LOAD_CONST 32 (0)
286 CALL_FUNCTION 1
289 POP_TOP
23 >> 290 BUILD_LIST 0
293 STORE_NAME 9 (x)
24 296 LOAD_CONST 40 (5)
299 STORE_NAME 10 (k)
25 302 SETUP_LOOP 128 (to 433)
305 LOAD_NAME 11 (range)
308 LOAD_CONST 41 (13)
311 CALL_FUNCTION 1
314 GET_ITER
>> 315 FOR_ITER 114 (to 432)
318 STORE_NAME 12 (i)
26 321 LOAD_NAME 8 (ord)
324 LOAD_NAME 4 (str)
327 LOAD_NAME 10 (k)
330 BINARY_SUBSCR
331 CALL_FUNCTION 1
334 STORE_NAME 13 (b)
27 337 LOAD_NAME 8 (ord)
340 LOAD_NAME 4 (str)
343 LOAD_NAME 10 (k)
346 LOAD_CONST 34 (1)
349 BINARY_ADD
350 BINARY_SUBSCR
351 CALL_FUNCTION 1
354 STORE_NAME 14 (c)
28 357 LOAD_NAME 14 (c)
360 LOAD_NAME 0 (en)
363 LOAD_NAME 12 (i)
366 LOAD_CONST 4 (6)
369 BINARY_MODULO
370 BINARY_SUBSCR
371 BINARY_XOR
372 STORE_NAME 15 (a11)
29 375 LOAD_NAME 13 (b)
378 LOAD_NAME 0 (en)
381 LOAD_NAME 12 (i)
384 LOAD_CONST 4 (6)
387 BINARY_MODULO
388 BINARY_SUBSCR
389 BINARY_XOR
390 STORE_NAME 16 (a22)
30 393 LOAD_NAME 9 (x)
396 LOAD_ATTR 17 (append)
399 LOAD_NAME 15 (a11)
402 CALL_FUNCTION 1
405 POP_TOP
31 406 LOAD_NAME 9 (x)
409 LOAD_ATTR 17 (append)
412 LOAD_NAME 16 (a22)
415 CALL_FUNCTION 1
418 POP_TOP
32 419 LOAD_NAME 10 (k)
422 LOAD_CONST 35 (2)
425 INPLACE_ADD
426 STORE_NAME 10 (k)
429 JUMP_ABSOLUTE 315
>> 432 POP_BLOCK
33 >> 433 LOAD_NAME 9 (x)
436 LOAD_NAME 1 (output)
439 COMPARE_OP 2 (==)
442 POP_JUMP_IF_FALSE 453
34 445 LOAD_CONST 38 ('good!continue\xe2\x80\xa6\xe2\x80\xa6')
448 PRINT_ITEM
449 PRINT_NEWLINE
450 JUMP_FORWARD 15 (to 468)
36 >> 453 LOAD_CONST 42 ('oh,you are wrong!')
456 PRINT_ITEM
457 PRINT_NEWLINE
37 458 LOAD_NAME 7 (exit)
461 LOAD_CONST 32 (0)
464 CALL_FUNCTION 1
467 POP_TOP
39 >> 468 LOAD_NAME 5 (len)
471 LOAD_NAME 4 (str)
474 CALL_FUNCTION 1
477 STORE_NAME 18 (l)
40 480 LOAD_NAME 8 (ord)
483 LOAD_NAME 4 (str)
486 LOAD_NAME 18 (l)
489 LOAD_CONST 43 (7)
492 BINARY_SUBTRACT
493 BINARY_SUBSCR
494 CALL_FUNCTION 1
497 STORE_NAME 19 (a1)
41 500 LOAD_NAME 8 (ord)
503 LOAD_NAME 4 (str)
506 LOAD_NAME 18 (l)
509 LOAD_CONST 4 (6)
512 BINARY_SUBTRACT
513 BINARY_SUBSCR
514 CALL_FUNCTION 1
517 STORE_NAME 20 (a2)
42 520 LOAD_NAME 8 (ord)
523 LOAD_NAME 4 (str)
526 LOAD_NAME 18 (l)
529 LOAD_CONST 40 (5)
532 BINARY_SUBTRACT
533 BINARY_SUBSCR
534 CALL_FUNCTION 1
537 STORE_NAME 21 (a3)
43 540 LOAD_NAME 8 (ord)
543 LOAD_NAME 4 (str)
546 LOAD_NAME 18 (l)
549 LOAD_CONST 36 (4)
552 BINARY_SUBTRACT
553 BINARY_SUBSCR
554 CALL_FUNCTION 1
557 STORE_NAME 22 (a4)
44 560 LOAD_NAME 8 (ord)
563 LOAD_NAME 4 (str)
566 LOAD_NAME 18 (l)
569 LOAD_CONST 0 (3)
572 BINARY_SUBTRACT
573 BINARY_SUBSCR
574 CALL_FUNCTION 1
577 STORE_NAME 23 (a5)
45 580 LOAD_NAME 8 (ord)
583 LOAD_NAME 4 (str)
586 LOAD_NAME 18 (l)
589 LOAD_CONST 35 (2)
592 BINARY_SUBTRACT
593 BINARY_SUBSCR
594 CALL_FUNCTION 1
597 STORE_NAME 24 (a6)
46 600 LOAD_NAME 19 (a1)
603 LOAD_CONST 0 (3)
606 BINARY_MULTIPLY
607 LOAD_NAME 20 (a2)
610 LOAD_CONST 35 (2)
613 BINARY_MULTIPLY
614 BINARY_ADD
615 LOAD_NAME 21 (a3)
618 LOAD_CONST 40 (5)
621 BINARY_MULTIPLY
622 BINARY_ADD
623 LOAD_CONST 44 (1003)
626 COMPARE_OP 2 (==)
629 POP_JUMP_IF_FALSE 807
47 632 LOAD_NAME 19 (a1)
635 LOAD_CONST 36 (4)
638 BINARY_MULTIPLY
639 LOAD_NAME 20 (a2)
642 LOAD_CONST 43 (7)
645 BINARY_MULTIPLY
646 BINARY_ADD
647 LOAD_NAME 21 (a3)
650 LOAD_CONST 3 (9)
653 BINARY_MULTIPLY
654 BINARY_ADD
655 LOAD_CONST 45 (2013)
658 COMPARE_OP 2 (==)
661 POP_JUMP_IF_FALSE 807
48 664 LOAD_NAME 19 (a1)
667 LOAD_NAME 20 (a2)
670 LOAD_CONST 46 (8)
673 BINARY_MULTIPLY
674 BINARY_ADD
675 LOAD_NAME 21 (a3)
678 LOAD_CONST 35 (2)
681 BINARY_MULTIPLY
682 BINARY_ADD
683 LOAD_CONST 47 (1109)
686 COMPARE_OP 2 (==)
689 POP_JUMP_IF_FALSE 804
49 692 LOAD_NAME 22 (a4)
695 LOAD_CONST 0 (3)
698 BINARY_MULTIPLY
699 LOAD_NAME 23 (a5)
702 LOAD_CONST 35 (2)
705 BINARY_MULTIPLY
706 BINARY_ADD
707 LOAD_NAME 24 (a6)
710 LOAD_CONST 40 (5)
713 BINARY_MULTIPLY
714 BINARY_ADD
715 LOAD_CONST 48 (671)
718 COMPARE_OP 2 (==)
721 POP_JUMP_IF_FALSE 801
50 724 LOAD_NAME 22 (a4)
727 LOAD_CONST 36 (4)
730 BINARY_MULTIPLY
731 LOAD_NAME 23 (a5)
734 LOAD_CONST 43 (7)
737 BINARY_MULTIPLY
738 BINARY_ADD
739 LOAD_NAME 24 (a6)
742 LOAD_CONST 3 (9)
745 BINARY_MULTIPLY
746 BINARY_ADD
747 LOAD_CONST 49 (1252)
750 COMPARE_OP 2 (==)
753 POP_JUMP_IF_FALSE 798
51 756 LOAD_NAME 22 (a4)
759 LOAD_NAME 23 (a5)
762 LOAD_CONST 46 (8)
765 BINARY_MULTIPLY
766 BINARY_ADD
767 LOAD_NAME 24 (a6)
770 LOAD_CONST 35 (2)
773 BINARY_MULTIPLY
774 BINARY_ADD
775 LOAD_CONST 50 (644)
778 COMPARE_OP 2 (==)
781 POP_JUMP_IF_FALSE 795
52 784 LOAD_CONST 51 ('congraduation!you get the right flag!')
787 PRINT_ITEM
788 PRINT_NEWLINE
789 JUMP_ABSOLUTE 795
792 JUMP_ABSOLUTE 798
>> 795 JUMP_ABSOLUTE 801
>> 798 JUMP_ABSOLUTE 804
>> 801 JUMP_ABSOLUTE 807
>> 804 JUMP_FORWARD 0 (to 807)
>> 807 LOAD_CONST 52 (None)
810 RETURN_VALUE
en = [3, 37, 72, 9, 6, 132]
output = [101, 96, 23, 68, 112, 42, 107, 62, 96, 53, 176, 179, 98, 53, 67, 29, 41, 120, 60, 106, 51, 101, 178, 189, 101,
48]
flag = input()
str1 = flag
if len(flag) < 38:
print("lenth wrong!")
exit(0)
s = ord(str1[0]) * 2020
s += ord(str1[1])
s *= 2020
s += ord(str1[2])
s *= 2020
s += ord(str1[3])
s *= 2020
s += ord(str1[4])
if s == 1182843538814603:
print('good!continue')
else:
exit()
x = []
k = 5
for i in range(13):
b = ord(str1[k])
c = ord(str1[k + 1])
a11 = c ^ en[i % 6]
a22 = b ^ en[i % 6]
x.append(a11)
x.append(a22)
k = k + 2
if x == output:
print('good!continue')
else:
exit()
l = len(str1)
a1 = ord(str1[l - 7])
a2 = ord(str1[l - 6])
a3 = ord(str1[l - 5])
a4 = ord(str1[l - 4])
a5 = ord(str1[l - 3])
a6 = ord(str1[l - 2])
if a1 * 3 + a2 * 2 + a3 * 5 == 1003:
if a1 * 4 + a2 * 7 + a3 * 9 == 2013:
if a1 + a2 * 8 + a3 * 2 == 1109:
if a4 * 3 + a5 * 2 + a6 * 5 == 671:
if a4 * 4 + a5 * 7 + a6 * 9 == 1252:
if a4 + a5 * 8 + a6 * 2 == 644:
print('congraduation!you get the right flag!')
首先分析第一段, 其实根据常识即可知道应该是GWHT{, 带入后正确
s = ord(str1[0]) * 2020
s += ord(str1[1])
s *= 2020
s += ord(str1[2])
s *= 2020
s += ord(str1[3])
s *= 2020
s += ord(str1[4])
if s == 1182843538814603:
print('good!continue')
else:
exit()
第二段分析, 可知为从第5位开始, 每两位进行某种异或运算, 而且其取值仅和output有关, 和前面和后面无关, 只有两位进行**即可
en = [3, 37, 72, 9, 6, 132]
output = [101, 96, 23, 68, 112, 42, 107, 62, 96, 53, 176, 179, 98, 53, 67, 29, 41, 120, 60, 106, 51, 101, 178, 189, 101,
48]
final = []
for zz in range(0, 26, 2):
def foo():
for xx in range(42, 127):
for yy in range(42, 127):
str1 = 'GWHT{' + f"{chr(xx)}{chr(yy)}" * 13
x = []
k = 5
for i in range(13):
b = ord(str1[k])
c = ord(str1[k + 1])
a11 = c ^ en[i % 6]
a22 = b ^ en[i % 6]
x.append(a11)
x.append(a22)
k += 2
if x[zz] == output[zz] and x[zz + 1] == output[zz + 1]:
final.append(xx)
final.append(yy)
return
print("fail", zz)
foo()
print("".join([chr(i) for i in final]))
>>> cfa2b87b3f746a8f0ac5c5963f
第三段, 又双叒叕是方程组, 这次怎么这么喜欢出方程组, z3直接解
from z3 import *
a1, a2, a3, a4, a5, a6 = Ints("a1 a2 a3 a4 a5 a6")
x = Solver()
x.add(a1 * 3 + a2 * 2 + a3 * 5 == 1003)
x.add(a1 * 4 + a2 * 7 + a3 * 9 == 2013)
x.add(a1 + a2 * 8 + a3 * 2 == 1109)
x.add(a4 * 3 + a5 * 2 + a6 * 5 == 671)
x.add(a4 * 4 + a5 * 7 + a6 * 9 == 1252)
x.add(a4 + a5 * 8 + a6 * 2 == 644)
x.check()
print(x.model())
for i in [97, 101, 102, 102, 55, 51]:
print(chr(i), end="")
>>> [a5 = 55, a2 = 101, a6 = 51, a3 = 102, a4 = 102, a1 = 97]
>>> aeff73
最后拼接一下cfa2b87b3f746a8f0ac5c5963faeff73
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