ATemp :TINT4;
  k_ipad :array [0..63] of UCHAR;    (* inner padding -
                                      * key XORd with ipad
                                      *)
  k_opad :array [0..63] of UCHAR;    (* outer padding -
                                      * key XORd with opad
                                      *)
  ABuffer :array [0..4196] of UCHAR;
  i :Integer;
  P :Pointer;
begin
  //記錄指針地址
  PBuffer :=FSrcCode;

  if AKeyLen>64 then
  begin
    FSrcCode :=AKey;
    FSrcCodeLen :=AKeyLen;
    MD5_Encode();
    ATemp :=FDesCode;
    AKey :=@ATemp;
    AKeyLen :=16;
  end;

  FSrcCode :=PBuffer;
  FillChar(k_ipad, SizeOf(k_ipad), #0);
  FillChar(k_opad, SizeOf(k_opad), #0);
  Move(AKey^, k_ipad, AKeyLen);
  Move(AKey^, k_opad, AKeyLen);
  for i :=0 to 63 do
  begin
    k_ipad[i] := k_ipad[i] xor $36;
    k_opad[i] := k_opad[i] xor $5c;
  end;
  
  //first Hash 將k_ipad同原字串合并， 并進行MD5加密
  FillChar(ABuffer, SizeOf(ABuffer), #0);
  Move(k_ipad, ABuffer[0], 64);
  Move(FSrcCode^, ABuffer[64], FSrcCodeLen);
  FSrcCode :=@ABuffer[0];
  FSrcCodeLen :=64 + FSrcCodeLen;
  MD5_Encode;
  ATemp :=FDesCode;
  
  //Sencond Hash 將k_opad同1過程得的結果合并 ，并進行MD5加密
  FillChar(ABuffer, SizeOf(ABuffer), #0);
  Move(k_opad, ABuffer[0], 64);
  Move(ATemp, ABuffer[64], 16);
  FSrcCode :=@ABuffer[0];
  FSrcCodeLen :=64 + 16;
  MD5_Encode;
  //恢復指針地址
  FSrcCode :=PBuffer;
end;

class function TMD5Code.MD5Encode(srcCode: string): string;
var
  AMD5Code :TMD5Code;
begin
  Result := '';
  AMD5Code :=TMD5Code.Create;
  try
    AMD5Code.SrcCode := PChar(Trim(srcCode));
    AMD5Code.MD5_Encode;
    Result := Trim(AMD5Code.GetHexValue(AMD5Code.DesCode));
  finally
    AMD5Code.Free;
  end;  
end;

function TMD5Code.ROL(val: LongWord; shift: Byte): LongWord; assembler;
asm
  mov  eax, val;
  mov  cl, shift;
  rol  eax, cl;
end;

function TMD5Code.ROR(val: LongWord; shift: Byte): LongWord; assembler;
asm
  mov  eax, val;
  mov  cl, shift;
  ror  eax, cl;
end;

//生成注冊碼
function GFUN_GetKey(Input_Str: string): string;
var
  j, k: integer;
  i: Longint;
  S: string;
begin
  S := Input_Str;
  i := 0;
  j := length(S);
  for k := 1 to j do
  begin
    i := i + k * Ord(S[k]);
  end;
  Result := Format('%x', [i]);
end;

function GFUN_Crypt(strText: string; intKey: longint=60): string;
var
  i: integer;
  strResult: string;
begin
  RandSeed := intKey;
  strResult := strText;
  for i := 1 to length(strText) do
    strResult[i] := chr(ord(strResult[i]) xor random(3));
  Result := strResult;
end;

function GFUN_Decrypt(strText: string; intKey: longint=60): string;
begin
  Result := GFUN_Crypt(strText, intKey);
end;


procedure initPermutation(var inData: array of Byte);
var
  newData: array[0..7] of Byte;
  i: Integer;
begin
  FillChar(newData, 8, 0);
  for i := 0 to 63 do
    if (inData[BitIP[i] shr 3] and (1 shl (7- (BitIP[i] and $07)))) <> 0 then
      newData[i shr 3] := newData[i shr 3] or (1 shl (7-(i and $07)));
  for i := 0 to 7 do inData[i] := newData[i];
end;

procedure conversePermutation(var inData: array of Byte);
var
  newData: array[0..7] of Byte;
  i: Integer;
begin
  FillChar(newData, 8, 0);
  for i := 0 to 63 do
    if (inData[BitCP[i] shr 3] and (1 shl (7-(BitCP[i] and $07)))) <> 0 then
      newData[i shr 3] := newData[i shr 3] or (1 shl (7-(i and $07)));
  for i := 0 to 7 do inData[i] := newData[i];
end;

procedure expand(inData: array of Byte; var outData: array of Byte);
var
  i: Integer;
begin
  FillChar(outData, 6, 0);
  for i := 0 to 47 do
    if (inData[BitExp[i] shr 3] and (1 shl (7-(BitExp[i] and $07)))) <> 0 then
      outData[i shr 3] := outData[i shr 3] or (1 shl (7-(i and $07)));
end;

procedure permutation(var inData: array of Byte);
var
  newData: array[0..3] of Byte;
  i: Integer;
begin
  FillChar(newData, 4, 0);
  for i := 0 to 31 do
    if (inData[BitPM[i] shr 3] and (1 shl (7-(BitPM[i] and $07)))) <> 0 then
      newData[i shr 3] := newData[i shr 3] or (1 shl (7-(i and $07)));
  for i := 0 to 3 do inData[i] := newData[i];
end;

function si(s,inByte: Byte): Byte;
var
  c: Byte;
begin
  c := (inByte and $20) or ((inByte and $1e) shr 1) or
    ((inByte and $01) shl 4);
  Result := (sBox[s][c] and $0f);
end;

procedure permutationChoose1(inData: array of Byte;
  var outData: array of Byte);
var
  i: Integer;
begin
  FillChar(outData, 7, 0);
  for i := 0 to 55 do
    if (inData[BitPMC1[i] shr 3] and (1 shl (7-(BitPMC1[i] and $07)))) <> 0 then
      outData[i shr 3] := outData[i shr 3] or (1 shl (7-(i and $07)));
end;

procedure permutationChoose2(inData: array of Byte;
  var outData: array of Byte);
var
  i: Integer;
begin
  FillChar(outData, 6, 0);
  for i := 0 to 47 do
    if (inData[BitPMC2[i] shr 3] and (1 shl (7-(BitPMC2[i] and $07)))) <> 0 then
      outData[i shr 3] := outData[i shr 3] or (1 shl (7-(i and $07)));
end;

procedure cycleMove(var inData: array of Byte; bitMove: Byte);
var
  i: Integer;
begin
  for i := 0 to bitMove - 1 do
  begin
    inData[0] := (inData[0] shl 1) or (inData[1] shr 7);
    inData[1] := (inData[1] shl 1) or (inData[2] shr 7);
    inData[2] := (inData[2] shl 1) or (inData[3] shr 7);
    inData[3] := (inData[3] shl 1) or ((inData[0] and $10) shr 4);
    inData[0] := (inData[0] and $0f);
  end;
end;

procedure makeKey(inKey: array of Byte; var outKey: array of TKeyByte);
const
  bitDisplace: array[0..15] of Byte =
    ( 1,1,2,2, 2,2,2,2, 1,2,2,2, 2,2,2,1 );
var
  outData56: array[0..6] of Byte;
  key28l: array[0..3] of Byte;
  key28r: array[0..3] of Byte;
  key56o: array[0..6] of Byte;
  i: Integer;
begin
  permutationChoose1(inKey, outData56);

  key28l[0] := outData56[0] shr 4;
  key28l[1] := (outData56[0] shl 4) or (outData56[1] shr 4);
  key28l[2] := (outData56[1] shl 4) or (outData56[2] shr 4);
  key28l[3] := (outData56[2] shl 4) or (outData56[3] shr 4);
  key28r[0] := outData56[3] and $0f;
  key28r[1] := outData56[4];
  key28r[2] := outData56[5];
  key28r[3] := outData56[6];

  for i := 0 to 15 do
  begin
    cycleMove(key28l, bitDisplace[i]);
    cycleMove(key28r, bitDisplace[i]);
    key56o[0] := (key28l[0] shl 4) or (key28l[1] shr 4);
    key56o[1] := (key28l[1] shl 4) or (key28l[2] shr 4);
    key56o[2] := (key28l[2] shl 4) or (key28l[3] shr 4);
    key56o[3] := (key28l[3] shl 4) or (key28r[0]);
    key56o[4] := key28r[1];
    key56o[5] := key28r[2];
    key56o[6] := key28r[3];
    permutationChoose2(key56o, outKey[i]);
  end;
end;

procedure encry(inData, subKey: array of Byte;
   var outData: array of Byte);
var
  outBuf: array[0..5] of Byte;
  buf: array[0..7] of Byte;
  i: Integer;
begin
  expand(inData, outBuf);
  for i := 0 to 5 do outBuf[i] := outBuf[i] xor subKey[i];
                                                // outBuf       xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
  buf[0] := outBuf[0] shr 2;                                  //xxxxxx -> 2
  buf[1] := ((outBuf[0] and $03) shl 4) or (outBuf[1] shr 4); // 4 <- xx xxxx -> 4
  buf[2] := ((outBuf[1] and $0f) shl 2) or (outBuf[2] shr 6); //        2 <- xxxx xx -> 6
  buf[3] := outBuf[2] and $3f;                                //                    xxxxxx
  buf[4] := outBuf[3] shr 2;                                  //                           xxxxxx
  buf[5] := ((outBuf[3] and $03) shl 4) or (outBuf[4] shr 4); //                                 xx xxxx
  buf[6] := ((outBuf[4] and $0f) shl 2) or (outBuf[5] shr 6); //                                        xxxx xx
  buf[7] := outBuf[5] and $3f;                                //                                               xxxxxx
  for i := 0 to 7 do buf[i] := si(i, buf[i]);
  for i := 0 to 3 do outBuf[i] := (buf[i*2] shl 4) or buf[i*2+1];
  permutation(outBuf);
  for i := 0 to 3 do outData[i] := outBuf[i];
end;

procedure desData(desMode: TDesMode;
  inData: array of Byte; var outData: array of Byte);
// inData, outData 都為8Bytes，否則出錯
var
  i, j: Integer;
  temp, buf: array[0..3] of Byte;
begin
  for i := 0 to 7 do outData[i] := inData[i];
  initPermutation(outData);
  if desMode = dmEncry then
  begin
    for i := 0 to 15 do
    begin
      for j := 0 to 3 do temp[j] := outData[j];                 //temp = Ln
      for j := 0 to 3 do outData[j] := outData[j + 4];	        //Ln+1 = Rn
      encry(outData, subKey[i], buf);                           //Rn ==Kn==> buf
      for j := 0 to 3 do outData[j + 4] := temp[j] xor buf[j];  //Rn+1 = Ln^buf
    end;

    for j := 0 to 3 do temp[j] := outData[j + 4];
    for j := 0 to 3 do outData[j + 4] := outData[j];
    for j := 0 to 3 do outData[j] := temp[j];
  end
  else if desMode = dmDecry then
  begin
    for i := 15 downto 0 do
    begin
      for j := 0 to 3 do temp[j] := outData[j];
      for j := 0 to 3 do outData[j] := outData[j + 4];
      encry(outData, subKey[i], buf);
      for j := 0 to 3 do outData[j + 4] := temp[j] xor buf[j];
    end;
    for j := 0 to 3 do temp[j] := outData[j + 4];
    for j := 0 to 3 do outData[j + 4] := outData[j];
    for j := 0 to 3 do outData[j] := temp[j];
  end;
  conversePermutation(outData);
end;

//////////////////////////////////////////////////////////////

function EncryStr(Str, Key: String): String;
var
  StrByte, OutByte, KeyByte: array[0..7] of Byte;
  StrResult: String;
  I, J: Integer;
begin
  if (Length(Str) > 0) and (Ord(Str[Length(Str)]) = 0) then
    raise Exception.Create('Error: the last char is NULL char.');
  if Length(Key) < 8 then
    while Length(Key) < 8 do Key := Key + Chr(0);
  while Length(Str) mod 8 <> 0 do Str := Str + Chr(0);

  for J := 0 to 7 do KeyByte[J] := Ord(Key[J + 1]);
  makeKey(keyByte, subKey);

  StrResult := '';

  for I := 0 to Length(Str) div 8 - 1 do
  begin
    for J := 0 to 7 do
      StrByte[J] := Ord(Str[I * 8 + J + 1]);
    desData(dmEncry, StrByte, OutByte);
    for J := 0 to 7 do
      StrResult := StrResult + Chr(OutByte[J]);
  end;

  Result := StrResult;
end;

function DecryStr(Str, Key: String): String;
var
  StrByte, OutByte, KeyByte: array[0..7] of Byte;
  StrResult: String;
  I, J: Integer;
begin
  if Length(Key) < 8 then
    while Length(Key) < 8 do Key := Key + Chr(0);

  for J := 0 to 7 do KeyByte[J] := Ord(Key[J + 1]);
  makeKey(keyByte, subKey);

  StrResult := '';

  for I := 0 to Length(Str) div 8 - 1 do
  begin
    for J := 0 to 7 do StrByte[J] := Ord(Str[I * 8 + J + 1]);
    desData(dmDecry, StrByte, OutByte);
    for J := 0 to 7 do
      StrResult := StrResult + Chr(OutByte[J]);
  end;
  while (Length(StrResult) > 0) and
    (Ord(StrResult[Length(StrResult)]) = 0) do
    Delete(StrResult, Length(StrResult), 1);
  Result := StrResult;
end;

///////////////////////////////////////////////////////////

function EncryStrHex(Str, Key: String): String;
var
  StrResult, TempResult, Temp: String;
  I: Integer;
begin
  TempResult := EncryStr(Str, Key);
  StrResult := '';
  for I := 0 to Length(TempResult) - 1 do
  begin
    Temp := Format('%x', [Ord(TempResult[I + 1])]);
    if Length(Temp) = 1 then Temp := '0' + Temp;
    StrResult := StrResult + Temp;
  end;
  Result := StrResult;
end;

function DecryStrHex(StrHex, Key: String): String;
  function HexToInt(Hex: String): Integer;
  var
    I, Res: Integer;
    ch: Char;
  begin
    Res := 0;
    for I := 0 to Length(Hex) - 1 do
    begin
      ch := Hex[I + 1];
      if (ch >= '0') and (ch <= '9') then
        Res := Res * 16 + Ord(ch) - Ord('0')
      else if (ch >= 'A') and (ch <= 'F') then
        Res := Res * 16 + Ord(ch) - Ord('A') + 10
      else if (ch >= 'a') and (ch <= 'f') then
        Res := Res * 16 + Ord(ch) - Ord('a') + 10
      else raise Exception.Create('Error: not a Hex String');
    end;
    Result := Res;
  end;

var
  Str, Temp: String;
  I: Integer;
begin
  Str := '';
  for I := 0 to Length(StrHex) div 2 - 1 do
  begin
    Temp := Copy(StrHex, I * 2 + 1, 2);
    Str := Str + Chr(HexToInt(Temp));
  end;
  Result := DecryStr(Str, Key);
end;


end.