File Encrypt / Decrypt

Encryption is the process of converting a file into a format that cannot be read by the applications set up to open the file. To remove the encryption you decrypt.

To encrypt or decrypt a file, simply click on the "Open" button, select an integer "masking" value and then click "(En/De) Crypt File". This little tool is ideal for offices that need to keep important documents secure.

unit UnitEnDecrypt;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ComCtrls, StdCtrls, Buttons, ExtCtrls;

type
  TEnDeCrypt = class(TForm)
    OpenDialog1: TOpenDialog;
    BtnOpen: TBitBtn;
    BtnEnDe: TBitBtn;
    GroupBox1: TGroupBox;
    Memo1: TMemo;
    GroupBox2: TGroupBox;
    leKey: TLabeledEdit;
    PageControl1: TPageControl;
    TabSheet1: TTabSheet;
    TabSheet2: TTabSheet;
    procedure BtnOpenClick(Sender: TObject);
    procedure BtnEnDeClick(Sender: TObject);
    procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
  private
    { Private declarations }
    procedure EnDecryptFile(pathin, pathout: string; Chave: Word);
  public
    { Public declarations }
  end;

var
  EnDeCrypt: TEnDeCrypt;

implementation

{$R *.dfm}

procedure TEnDeCrypt.EnDecryptFile(pathin, pathout: string; Chave: Word);
var
  InMS, OutMS: TMemoryStream;
  cnt: Integer;
  C: byte;
begin
  InMS  := TMemoryStream.Create;
  OutMS := TMemoryStream.Create;
  try
    InMS.LoadFromFile(pathin);
    InMS.Position := 0;
    for cnt := 0 to InMS.Size - 1 DO
      begin
        InMS.Read(C, 1);
        C := (C xor not (ord(chave shr cnt)));
        OutMS.Write(C, 1);
      end;
    OutMS.SaveToFile(pathout);
  finally
    InMS.Free;
    OutMS.Free;
  end;
end;

procedure TEnDeCrypt.BtnOpenClick(Sender: TObject);
begin
  OpenDialog1.Execute;
end;

procedure TEnDeCrypt.BtnEnDeClick(Sender: TObject);
begin
  IF MessageDlg('ATTENTION'+#13+
                'Do not miss the password, or lose the file!',
                mtConfirmation, [mbYes, mbNo], 0) = mrYes THEN
    BEGIN
      EnDecryptFile(OpenDialog1.FileName, OpenDialog1.FileName, StrToInt(leKey.Text));
      ShowMessage('Operation completed successfully!');
    END;
end;

procedure TEnDeCrypt.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
var
  aux: integer;
begin
  IF GroupBox1.Height = 83 THEN
    BEGIN
      FOR aux := 83 DOWNTO 18 DO
        GroupBox1.Height := aux;
    END;
end;

end.

Source

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