一个游戏客户端文件的字节加解密代码，我花1000元请人解的，存在这，以后应该用得到。...-优快云博客

本文提供了一种用于内存中数据加密和解密的算法实现。该算法通过循环操作修改内存中的DWORD值来达到加密和解密的目的。每轮操作涉及复杂的位运算和常量调整，确保了数据的安全性。

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代码

procedure EncryptMemory(Data: Pointer; Size: Cardinal);
  procedure EncryptData(var A, B: DWORD);
  var
    _Constant, i: DWORD;
  begin
    _Constant := 0;
    for i := 0 to 31 do
    begin
      _Constant := _Constant - $61C88647;
      A := A + (((B shr 5) + $2B4805C2) xor ((B shl 4) + $98DFF541) xor (B + _Constant));
      B := B + (((A shr 5) + $D8144BA5) xor ((A shl 4) + $01AF979B) xor (A + _Constant));
    end;
  end;

var
  i: Integer;
  _Data1, _Data2: Dword;
begin
  for I := 0 to (Size div 8) - 1 do
  begin
    _Data1 := Pdword(dword(Data) + (i * 8))^;
    _Data2 := Pdword(dword(Data) + (i * 8) + 4)^;
    EncryptData(_Data1, _Data2);
    Pdword(dword(Data) + (i * 8))^ := _Data1;
    Pdword(dword(Data) + (i * 8) + 4)^ := _Data2;
  end;
end;

procedure DecryptMemory(Data: Pointer; Size: Cardinal);
  procedure DecryptData(var A, B: DWORD);
  var
    _Constant, i: DWORD;
  begin
    _Constant := $C6EF3720;
    for i := 0 to 31 do
    begin
      B := B - (((A shr 5) + $D8144BA5) xor ((A shl 4) + $01AF979B) xor (A + _Constant));
      A := A - (((B shr 5) + $2B4805C2) xor ((B shl 4) + $98DFF541) xor (B + _Constant));
      _Constant := _Constant + $61C88647;
    end;
  end;
var
  i: Integer;
  _Data1, _Data2: Dword;
begin
  for I := 0 to (Size div 8) - 1 do
  begin
    _Data1 := Pdword(dword(Data) + (i * 8))^;
    _Data2 := Pdword(dword(Data) + (i * 8) + 4)^;
    DecryptData(_Data1, _Data2);
    Pdword(dword(Data) + (i * 8))^ := _Data1;
    Pdword(dword(Data) + (i * 8) + 4)^ := _Data2;
  end;
end;

//使用
procedure TfrmMain.btn1Click(Sender: TObject);
var
  memStream: TMemoryStream;
begin
  memStream := TMemoryStream.Create;
  memStream.LoadFromFile('.\732');
  DecryptMemory(memStream.Memory, memStream.Size);
  memStream.SaveToFile('.\732_u');
  FreeAndNil(memStream);
end;

转载于:https://www.cnblogs.com/jxgxy/archive/2010/04/21/1717590.html