例题

1、进制转换

负数的16进制要用补码来表示

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int __cdecl main(int argc, const char **argv, const char **envp)
{
  size_t v3; // rax
  int v5; // [rsp+Ch] [rbp-134h] BYREF
  unsigned int i; // [rsp+10h] [rbp-130h]
  int v7; // [rsp+14h] [rbp-12Ch]
  int v8; // [rsp+18h] [rbp-128h]
  int v9; // [rsp+1Ch] [rbp-124h]
  int v10; // [rsp+20h] [rbp-120h]
  int v11; // [rsp+24h] [rbp-11Ch]
  int v12; // [rsp+28h] [rbp-118h]
  int v13; // [rsp+2Ch] [rbp-114h]
  int v14; // [rsp+30h] [rbp-110h]
  int v15; // [rsp+34h] [rbp-10Ch]
  unsigned __int64 v16; // [rsp+38h] [rbp-108h]
  int v17[8]; // [rsp+40h] [rbp-100h]
  char s[5]; // [rsp+60h] [rbp-E0h] BYREF
  char v19[107]; // [rsp+65h] [rbp-DBh] BYREF
  char dest[104]; // [rsp+D0h] [rbp-70h] BYREF
  unsigned __int64 v21; // [rsp+138h] [rbp-8h]

  v21 = __readfsqword(0x28u);
  v7 = 80;
  v8 = 64227;
  v9 = 226312059;
  v10 = -1540056586;
  v11 = 5;
  v12 = 16;
  v13 = 3833;
  v5 = 0;
  puts("plz input the key:");
  __isoc99_scanf("%s", s);
  v3 = strlen(s);
  strncpy(dest, v19, v3 - 6);
  dest[strlen(s) - 6] = 0;
  __isoc99_sscanf(dest, "%x", &v5);
  v17[0] = v7;
  v17[1] = v8;
  v17[2] = v9;
  v17[3] = v10;
  v17[4] = (v11 << 12) + v12;
  v17[5] = v13;
  v17[6] = v5;
  v16 = 0LL;
  for ( i = 0; i <= 6; ++i )
  {
    for ( v16 += (unsigned int)v17[i]; v16 > 0xFFFF; v16 = v15 + (unsigned int)(unsigned __int16)v16 )
    {
      v14 = (unsigned __int16)v16;
      v15 = v16 >> 16;
    }
  }
  if ( v16 == 0xFFFF )
    puts("OK");
  else
    puts("Error");
  return 0;
}

1715339407886-4f402e28-e9ee-42fc-b0a7-e9ddbe39c300.png

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v7 = 80
v8 = 64227
v9 = 226312059
v10 = -1540056586
v11 = 5
v12 = 16
v13 = 3833
for x in range(0xffff):
    v17 = [v7, v8, v9,0xA43499F6, (v11 << 12) + v12, v13, x]
    v16 = 0
    for i in range(7):
        v16 += v17[i]
        while v16 > 0xffff:
                v15 = v16 >> 16
                v16 = (v15 + (v16 & 0xffff)) & 0xffffffff
    if v16 == 0xffff:
        print(hex(x))

更新: 2024-07-19 09:58:00
原文: https://www.yuque.com/chaye-apqbl/vsc85q/dw6mf4rvefpa7omi

http://example.com/2026/01/19/RE/例题/index/
Author
chaye
Posted on
January 19, 2026
Licensed under