char __thiscall GetKey(struct_this *this, size_t Size)
{
  char result; // bl
  void *buff; // eax

  result = 1;
  if ( Size <= this->someSize )
    goto LABEL_11;
  result = 0;
  if ( this->ptrBuff )
    free(this->ptrBuff);
  buff = malloc(Size);
  this->ptrBuff = buff;
  if ( buff )
  {
    this->someSize = Size;
    result = 1;
  }
  ++this->someCounter;
  if ( result )
  {
LABEL_11:
    _mm_storel_epi64(&this->key1dest, _mm_loadl_epi64(&this->key1src));
    _mm_storel_epi64(&this->key2dest, _mm_loadl_epi64(&this->key2src));
  }
  return result;
}

int __thiscall sub_543AD0(struct_this *this, void *Dst, int a3, int a4)
{
  int v5; // eax
  int v6; // edi
  int result; // eax
  DWORD time; // [esp+8h] [ebp-Ch]
  int *decryptedBuff; // [esp+Ch] [ebp-8h]
  int Size; // [esp+10h] [ebp-4h]

  v5 = this->dword1178;
  if ( v5 )
  {
    if ( a4 < v5 )
    {
      Size = a4;
      goto LABEL_6;
    }
  }
  else
  {
    v5 = a4;
  }
  Size = v5;
LABEL_6:
  if ( this->dword1180 != 2 )
    return 0;
  if ( !GetKey(this, Size) )                    // get key
    return 0;
  time = GetTickCount();
  decryptedBuff = this->ptrBuff;
  v6 = DecryptBuffer(&this->byte113C, &this->dword18, Dst, 8 * Size, decryptedBuff);// do decryption
  if ( v6 == 8 * Size )
    memcpy(Dst, decryptedBuff, Size);           // copy data, is decrypted here
  this->timeElapsed += GetTickCount() - time;
  this->dwordC += a4;
  ++this->dword8;
  result = v6;
  if ( v6 != a4 )
    ++this->dword14;
  return result;
}