unit1.pas

Delphi7开发的DES字符串加密解密例子,相信在程序里能用得到

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, StrUtils;

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Edit2: TEdit;
    Button1: TButton;
    Button2: TButton;
    Label1: TLabel;
    Label2: TLabel;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private

  public

  end;

//type
//  TDynByteArray = array of byte;

const
  SeedA             = 5678;   /// 常量，你可以修改
  SeedB             = 5432;   /// 常量，你可以修改

var
  Form1: TForm1;

implementation

{$R *.dfm}

/// 字符串
function Crypt(const s: string; Key: Word; const bEncrypt: boolean = True): string; overload;
var
  i                 : integer;
  ps, pr            : ^byte;
begin
  SetLength(Result, Length(s));
  ps := @s[1];
  pr := @Result[1];
  for i := 1 to length(s) do
  begin
    pr^ := ps^ xor (Key shr 8);
    if bEncrypt then
      Key := (pr^ + Key) * SeedA + SeedB
    else
      Key := (ps^ + Key) * SeedA + SeedB;
    pr := pointer(integer(pr) + 1);
    ps := pointer(integer(ps) + 1);
  end
end;

//加密
procedure TForm1.Button1Click(Sender: TObject);
begin
  Edit2.Text := Crypt(Edit1.Text,10);
end;

//解密
procedure TForm1.Button2Click(Sender: TObject);
begin
  //Edit1.Text := DecStr(Edit2.Text);
end;

end.