代码效果如下

按钮1是将edit1内容加密，并存入text文件中，按钮2是在text文件中读取加密后的内容，并解密。

unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, EncdDecd,StdCtrls;type TForm1 = class(TForm) edt1: TEdit; edt2: TEdit; edt3: TEdit; btn1: TButton; btn2: TButton; procedure FormCreate(Sender: TObject); procedure btn1Click(Sender: TObject); procedure btn2Click(Sender: TObject); private { Private declarations } public { Public declarations } end;var Form1: TForm1; t:Text; f:string; implementation{$R *.dfm}procedure TForm1.btn1Click(Sender: TObject);begin edt2.Text:=EncodeString(edt1.Text); if FileExists(f) then begin AssignFile(t,f); end else begin AssignFile(t,f); Rewrite(t); end; Append(t); Writeln(t,edt2.text); CloseFile(t);end;procedure TForm1.btn2Click(Sender: TObject);vars:string;begin if FileExists(f) then begin AssignFile(t,f); Reset(t); while not Eof(t) do Readln(t,s); edt3.Text:=DecodeString(s); end; CloseFile(t);end;procedure TForm1.FormCreate(Sender: TObject);begin f:=ExtractFilePath(ParamStr(0))+'text.txt';end;end.