암호화 관련 소스 입니다.

아래와 같은데..... 도무지 어려운 말이 많아서...

아시는분 주석점 부탁드립니다......

Function EncryptionWithPassword(Str,Pwd: String; Encode: Boolean): String;
var
  a,PwdChk,Direction,ShiftVal,PasswordDigit : Integer;
begin
  PasswordDigit := 1;
  PwdChk := 0;
  for a := 1 to Length(Pwd) do Inc(PwdChk,Ord(Pwd[a]));
  Result := Str;
  if Encode then Direction := -1 else Direction := 1;
  for a := 1 to Length(Result) do
    begin
      if Length(Pwd)=0 then
        ShiftVal := a
      else
        ShiftVal := Ord(Pwd[PasswordDigit]);
      if Odd(A) then
        Result[A] := RotateBits(Result[A],-Direction*(ShiftVal+PwdChk))
      else
        Result[A] := RotateBits(Result[A],Direction*(ShiftVal+PwdChk));
      inc(PasswordDigit);
      if PasswordDigit > Length(Pwd) then PasswordDigit := 1;
    end;
end;



Function RotateBits(C: Char; Bits: Integer): Char;
var
  SI : Word;
begin
  Bits := Bits mod 8;
  if Bits < 0 then
    begin
      SI := MakeWord(Byte(C),0);
      SI := SI shl Abs(Bits);
    end
  else
    begin
      SI := MakeWord(0,Byte(C));
       SI := SI shr Abs(Bits);
    end;
  SI := Swap(SI);
  SI := Lo(SI) or Hi(SI);
  Result := Chr(SI);
end;