Source code program encrypt and decrypt dengan bahasa pascal

Program encypt decrypt ini merupakan program yang digunakan untuk membuat pesan rahasia.Program dibawah ini mempunyai kunci untuk encrypt = alfabet + 3. Sedangkan untuk decrypt mempunyai rumus sebaliknya.

program enkripsi_diskripsi;
uses wincrt;
var
   i : byte;
   kata : string;
   kunci,pil : char;
Procedure menu;
forward;
Procedure input;
  begin
   gotoxy(1,5);write ('Write a word : '); readln (kata);
  end;
  
Procedure enkripsi;
  begin
   clrscr;
   gotoxy(1,2);writeln('ENKRIPSI');
   gotoxy(1,3);writeln('====================');
   input;
      for i:=1 to length(kata) do
        begin
          kata[i]:=chr(ord(kata[i])+ 3);
           if (kata[i] in ['A'..'Z']) or (kata[i] in ['a'..'z']) then kata[i] := kata[i]
           else
          kata[i] := chr(ord(kata[i])- 26);
        end;
   gotoxy(1,7);write ('Result of Enkripsi : ',kata);
   gotoxy(15,24);write('==== Press Enter to return Menu ==== ');
   readln;
   menu;
   end;
Procedure dekripsi;
  begin                                  
  clrscr;
  gotoxy(1,2);writeln('DEKRIPSI');
  gotoxy(1,3);writeln('====================');
  input;
    for i :=1 to length(kata) do
      begin
       kata[i]:=chr(ord(kata[i]) - 3);
        if (kata[i] in ['A'..'Z']) or (kata[i] in ['a'..'z']) then kata[i] := kata[i]
        else
       kata[i] := chr(ord(kata[i]) + 26)
      end;
  gotoxy(1,7);write ('Hasil Dekripsi : ',kata);
  gotoxy(15,24);write('==== Press Enter to Return Menu ==== ');
  readln;
  menu;
  end;
Procedure menu;
var
  pil : char;
begin
clrscr;
repeat
gotoxy(16,9); writeln(' ========================');
gotoxy(16,10);writeln(' NAMA : RIKY BAGUS.M ');
gotoxy(16,11);writeln(' NIM : M0508117 ');
gotoxy(16,12);writeln(' ========================');
gotoxy(21,15);writeln(' MENU ');
gotoxy(22,16);writeln('1. Enkripsi Massange');
gotoxy(22,17);writeln('2. Dekripsi Massange');
gotoxy(22,18);writeln('3. Exit ');
gotoxy(16,20);writeln('Your Choise : ');
gotoxy(31,20);readln(pil);
until (pil in ['1','2','3']);
case pil of
'1' : enkripsi;
'2' : dekripsi;
'3' : donewincrt;
end;
end;
begin
menu;
end.

Jika program diatas kita run maka akan menghasilkan output seperti dibawah ini :

Untuk output program encrypt

Sedangkan output program decrypt