32 Bit Fence String Crypter

// Crypt
procedure TForm1.Button1Click(Sender: TObject);
var kp,kt,kkurz,kz:string;
    zyk,j,i,n,i2,l:integer;
begin
    kt:='';
    kz:='';
    memo2.clear;
    for i:=0 to memo1.lines.count-1 do
    begin
      kp:=memo1.lines.Strings[i];
      kt:=kt+kp;
    end;
    n:=strtoint(edit1.text);
    l:=length(kt);
    if l>0 then
    begin
      if (n<3) or (n>200) then
      begin
        n:=3;
        edit1.text:='3'
      end;

      if checkbox1.checked then
      begin
        kkurz:='';
        for i:=1 to l do
            if kt[i] in ['0'..'9','a'..'z','A'..'Z','ä','ö','ü','ß','Ä','Ö','Ü']
            then kkurz:=kkurz+kt[i];
      end
      else
        kkurz:=kt;

      l:=length(kkurz);
      zyk:=2*n-2;
      i:=1;
      repeat
        kz:=kz+kkurz[i];
        i:=i+zyk;
      until i>l;

      j:=2;
      repeat
        i:=j;
        i2:=zyk-j+2;
        repeat
          kz:=kz+kkurz[i];
          if i2<=l then kz:=kz+kkurz[i2];
          i:=i+zyk;
          i2:=i2+zyk;
        until i>l;
        j:=j+1;
      until j>(n-1);

      i:=n;
      repeat
        kz:=kz+kkurz[i];
        i:=i+zyk;
      until i>l;

      if checkbox1.checked then
      begin
        j:=1;
        for i:=1 to length(kt) do
          if kt[i] in ['0'..'9','a'..'z','A'..'Z','ä','ö','ü','ß','Ä','Ö','Ü']
             then
             begin
               kt[i]:=kz[j];
               inc(j);
             end;
      end
      else
        kt:=kz;

      memo2.lines.add(kt);
    end;
end;

// Decrypt
procedure TForm1.Button2Click(Sender: TObject);
var kp,kt,kz,kkurz:string;
    zyk,j,i,n,i2,i3:integer;
begin
    kt:='';
    memo1.clear;
    for i:=0 to memo2.lines.count-1 do
    begin
      kp:=memo2.lines.Strings[i];
      kt:=kt+kp;
    end;
    if length(kt)>0 then
    begin
      n:=strtoint(edit1.text);
      if (n<3) or (n>200) then
      begin
        n:=3;
        edit1.text:='3'
      end;

      if checkbox1.checked then
      begin
        kkurz:='';
        for i:=1 to length(kt) do
          if kt[i] in ['0'..'9','a'..'z','A'..'Z','ä','ö','ü','ß','Ä','Ö','Ü']
            then kkurz:=kkurz+kt[i];
      end
      else
        kkurz:=kt;

      zyk:=2*n-2;
      kz:=kkurz;
      i:=1;
      j:=1;
      repeat
        kz[j]:=kkurz[i];
        j:=j+zyk;
        inc(i);
      until j>length(kkurz{kt});

      j:=2;
      repeat
        i3:=j;
        i2:=zyk-j+2;
        repeat
          kz[i3]:=kkurz[i];
          inc(i);
          if i2<=length(kkurz) then
          begin
            kz[i2]:=kkurz[i];
            inc(i);
          end;
          i3:=i3+zyk;
          i2:=i2+zyk;
        until i3>length(kkurz);
        inc(j);
      until j>n-1;

      j:=n;
      repeat
        kz[j]:=kkurz[i];
        j:=j+zyk;
        inc(i);
      until j>length(kkurz);

      if checkbox1.checked then
      begin
        j:=1;
        for i:=1 to length(kt) do
          if kt[i] in ['0'..'9','a'..'z','A'..'Z','ä','ö','ü','ß','Ä','Ö','Ü']
             then
             begin
               kt[i]:=kz[j];
               inc(j);
             end;
       end
       else
         kt:=kz;

       memo1.lines.add(kt);
    end;
end;