Function SecHideData

Libraries/unrar/secpassword.cpp:166–216

void SecHideData(void *Data,size_t DataSize,bool Encode,bool CrossProcess)
{
  // CryptProtectMemory is not available in UWP and CryptProtectData
  // increases data size not allowing in place conversion.
#if defined(_WIN_ALL)
  // Try to utilize the secure Crypt[Un]ProtectMemory if possible.
  if (GlobalCryptLoader.pCryptProtectMemory==NULL)
    GlobalCryptLoader.Load();
  size_t Aligned=DataSize-DataSize%CRYPTPROTECTMEMORY_BLOCK_SIZE;
  DWORD Flags=CrossProcess ? CRYPTPROTECTMEMORY_CROSS_PROCESS : CRYPTPROTECTMEMORY_SAME_PROCESS;
  if (Encode)
  {
    if (GlobalCryptLoader.pCryptProtectMemory!=NULL)
    {
      if (!GlobalCryptLoader.pCryptProtectMemory(Data,DWORD(Aligned),Flags))
      {
        ErrHandler.GeneralErrMsg(L"CryptProtectMemory failed");
        ErrHandler.SysErrMsg();
        ErrHandler.Exit(RARX_FATAL);
      }
      return;
    }
  }
  else
  {
    if (GlobalCryptLoader.pCryptUnprotectMemory!=NULL)
    {
      if (!GlobalCryptLoader.pCryptUnprotectMemory(Data,DWORD(Aligned),Flags))
      {
        ErrHandler.GeneralErrMsg(L"CryptUnprotectMemory failed");
        ErrHandler.SysErrMsg();
        ErrHandler.Exit(RARX_FATAL);
      }
      return;
    }
  }
#endif
  
  // CryptProtectMemory is not available, so only slightly obfuscate data.
  uint Key;
#ifdef _WIN_ALL
  Key=GetCurrentProcessId();
#elif defined(_UNIX)
  Key=getpid();
#else
  Key=0; // Just an arbitrary value.
#endif

  for (size_t I=0;I<DataSize;I++)
    *((byte *)Data+I)^=Key+I+75;
}