1import gmpy2
 2# 解密函数
 3def affine_decrypt(ciphertext,a,b):
 4    plaintext=''
 5    inver_a=gmpy2.invert(a,26)
 6    for char in ciphertext:
 7        if char.isalpha():
 8            # 获取字母次序
 9            char_num = ord(char) - ord('a')
10            decrypted_char_num = (inver_a * (char_num - b)) % 26
11            # 得到密文字母次序，要加上a的ascii才能得到此密文字母的ascii
12            decrypted_char = chr(decrypted_char_num + ord('a'))
13            plaintext += decrypted_char
14        else:
15            plaintext += char
16    
17    return plaintext
18
19def brute_force(ciphertext):
20    for a in range(1, 26):
21        for b in range(26):
22            if gmpy2.gcd(a,26)==1:
23                plaintext = affine_decrypt(ciphertext, a, b)
24                print(f"参数：a={a}，b={b} 解密：{plaintext}")
25                # 输出太多还要搜索，这里设置如果是flag开头直接停止函数
26                if plaintext[:4]=="flag":
27                    return 0
28            else:
29                continue
30
31ciphertext = 'aipx{823j56p37ap92p93pd4g7ad6a0p01p21}'
32brute_force(ciphertext)

 1// main.main
 2void __fastcall main_main()
 3{
 4  string *v0; // rcx
 5  __int64 v1; // rax
 6  __int64 r1; // rdx
 7  __int64 r0; // rbx
 8  retval_44A060 v4; // kr00_16
 9  retval_449800 v5; // kr10_16
10  char *ptr; // rdi
11  __int64 v7; // [rsp+0h] [rbp-68h]
12  __int64 v8; // [rsp+8h] [rbp-60h]
13  __int64 v9; // [rsp+10h] [rbp-58h]
14  string *p_string; // [rsp+18h] [rbp-50h]
15  _QWORD v11[2]; // [rsp+20h] [rbp-48h] BYREF
16  _QWORD v12[2]; // [rsp+30h] [rbp-38h] BYREF
17  _QWORD v13[2]; // [rsp+40h] [rbp-28h] BYREF
18  _QWORD v14[2]; // [rsp+50h] [rbp-18h] BYREF
19
20  p_string = (string *)runtime_newobject(&RTYPE_string);
21  p_string->ptr = 0;
22  v14[0] = &RTYPE__ptr_string;
23  v14[1] = p_string;
24  fmt_Fscanf(go_itab__os_File_io_Reader, os_Stdin, "%s", 2, v14, 1, 1);
25  v0 = p_string;
26  if ( p_string->len == 32 )
27  {
28    v1 = 0;
29    r1 = 0;
30    r0 = 0;
31    while ( v1 < 32 )
32    {
33      ptr = v0->ptr;
34      if ( v1 >= v0->len )
35        runtime_panicIndex(v1, r0, v0->len, ptr);
36      v7 = r1;
37      v9 = r0;
38      v8 = v1 + 1;
39      v4 = runtime_intstring(0, (unsigned __int8)((v1 + 1) ^ ptr[v1]));
40      v5 = runtime_concatstring2(0, v9, v7, v4._r0, v4._r1);
41      v0 = p_string;
42      r1 = v5._r1;
43      r0 = v5._r0;
44      v1 = v8;
45    }
46    if ( r1 == 31 && (unsigned __int8)runtime_memequal(r0, "66a<254?=??>=>k$u! r-&t,/,(x~+z", 31) )
47    {
48      v12[0] = &RTYPE_string;
49      v12[1] = &off_4DBE00;
50      fmt_Fprintln(go_itab__os_File_io_Writer, os_Stdout, v12, 1, 1);
51    }
52    else
53    {
54      v11[0] = &RTYPE_string;
55      v11[1] = &off_4DBE10;
56      fmt_Fprintln(go_itab__os_File_io_Writer, os_Stdout, v11, 1, 1);
57    }
58  }
59  else
60  {
61    v13[0] = &RTYPE_string;
62    v13[1] = &off_4DBDF0;
63    fmt_Fprintln(go_itab__os_File_io_Writer, os_Stdout, v13, 1, 1);
64  }
65}