_decode.pas

传世源码可编译的,功能齐全.是学习的好模版,会DELPHI的朋友们也可以自己修改,弄个自己的引擎.

   begin
    b := InPtr^;
    b := b shl 4;
    OutPtr.b2 := MIME_ENCODE_TABLE[b and $3F];
    b := b shr 6;
    OutPtr.b1 := MIME_ENCODE_TABLE[b];
    OutPtr.b3 := MIME_PAD_CHAR;
    OutPtr.b4 := MIME_PAD_CHAR;
   end;
  2:
   begin
    b := InPtr^;
    Inc (InPtr);
    b := b shl 8;
    b := b or InPtr^;
    b := b shl 2;
    OutPtr.b3 := MIME_ENCODE_TABLE[b and $3F];
    b := b shr 6;
    OutPtr.b2 := MIME_ENCODE_TABLE[b and $3F];
    b := b shr 6;
    OutPtr.b1 := MIME_ENCODE_TABLE[b];
    OutPtr.b4 := MIME_PAD_CHAR;         { Pad remaining byte. }
   end;
 end;
end;

function MimeDecode (const InputBuffer; const InputBytesCount: Cardinal;
  out OutputBuffer): Cardinal;
var
 ByteBuffer, ByteBufferSpace: Cardinal;
begin
 ByteBuffer := 0;
 ByteBufferSpace := 4;
 Result := MimeDecodePartial(InputBuffer, InputBytesCount,
  OutputBuffer, ByteBuffer, ByteBufferSpace);
 Inc (Result, MimeDecodePartialEnd(Pointer (Cardinal(@OutputBuffer) + Result)^,
  ByteBuffer, ByteBufferSpace));
end;

function MimeDecodePartial (const InputBuffer; const InputBytesCount: Cardinal;
  out OutputBuffer; var ByteBuffer: Cardinal; var ByteBufferSpace: Cardinal): Cardinal;
var
 lByteBuffer, lByteBufferSpace, c: Cardinal;
 InPtr, OuterLimit  : ^Byte;
 OutPtr             : PByte3;
begin
 if InputBytesCount > 0 then
  begin
   InPtr := @InputBuffer;
   Cardinal (OuterLimit) := Cardinal (InPtr) + InputBytesCount;
   OutPtr := @OutputBuffer;
   lByteBuffer := ByteBuffer;
   lByteBufferSpace := ByteBufferSpace;
   while InPtr <> OuterLimit do
    begin
     c := MIME_DECODE_TABLE[InPtr^];
     Inc (InPtr);
     if c = $FF then Continue;
     lByteBuffer := lByteBuffer shl 6;
     lByteBuffer := lByteBuffer or c;
     Dec (lByteBufferSpace);
     if lByteBufferSpace <> 0 then Continue;
     OutPtr^.b3 := Byte (lByteBuffer);
     lByteBuffer := lByteBuffer shr 8;
     OutPtr^.b2 := Byte (lByteBuffer);
     lByteBuffer := lByteBuffer shr 8;
     OutPtr^.b1 := Byte (lByteBuffer);
     lByteBuffer := 0;
     Inc (OutPtr);
     lByteBufferSpace := 4;
    end;
   ByteBuffer := lByteBuffer;
   ByteBufferSpace := lByteBufferSpace;
   Result := Cardinal (OutPtr) - Cardinal (@OutputBuffer);
  end
 else
  Result := 0;
end;

function MimeDecodePartialEnd (out OutputBuffer; const ByteBuffer: Cardinal; 
  const ByteBufferSpace: Cardinal): Cardinal;
var
 lByteBuffer : Cardinal;
begin
 case ByteBufferSpace of
  1:
   begin
    lByteBuffer := ByteBuffer shr 2;
    PByte3 (@OutputBuffer)^.b2 := Byte (lByteBuffer);
    lByteBuffer := lByteBuffer shr 8;
    PByte3 (@OutputBuffer)^.b1 := Byte (lByteBuffer);
    Result := 2;
   end;
  2:
   begin
    lByteBuffer := ByteBuffer shr 4;
    PByte3 (@OutputBuffer)^.b1 := Byte (lByteBuffer);
    Result := 1;
   end;
  else
   Result := 0;
 end;
end;

procedure Base64Encode(InputFile, OutputFile: string);
var
  Ms: TMemoryStream;
  Ss: TStringStream;
  Str: string;
  List: TStringList;
begin {Base64 encode} 
  Ms := TMemoryStream.Create;
  try
    Ms.LoadFromFile(InputFile);
    Ss := TStringStream.Create(Str);
    try
      MimeEncodeStream(Ms, Ss);
      List := TStringList.Create;
      try
        List.Text := Ss.DataString;
        List.SaveToFile(OutputFile);
      finally
        List.Free;
      end;
    finally
      Ss.Free;
    end;
  finally
    Ms.Free;
  end;
end;

procedure Base64Decode(InputFile, OutputFile: string);
var
  Ms: TMemoryStream;
  Ss: TStringStream;
  List: TStringList;
begin {Base64 decode}
  List := TStringList.Create;
  try
    List.LoadFromFile(InputFile);
    Ss := TStringStream.Create(List.Text);
    try
      Ms := TMemoryStream.Create;
      try
        MimeDecodeStream(Ss, Ms);
        Ms.SaveToFile(OutputFile);
      finally
        Ms.Free;
      end;
    finally
      Ss.Free;
    end;
  finally
    List.Free;
  end;
end;
//......................Base64 End

//......................Des Start
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];
  buf[0] := outBuf[0] shr 2;
  buf[1] := ((outBuf[0] and $03) shl 4) or (outBuf[1] shr 4);
  buf[2] := ((outBuf[1] and $0f) shl 2) or (outBuf[2] shr 6);
  buf[3] := outBuf[2] and $3f;
  buf[4] := outBuf[3] shr 2;
  buf[5] := ((outBuf[3] and $03) shl 4) or (outBuf[4] shr 4);
  buf[6] := ((outBuf[4] and $0f) shl 2) or (outBuf[5] shr 6);
  buf[7] := outBuf[5] and $3f;                                
  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 都为8Bytes，否则出错
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;
//.....................Des End

function My_Encode(Str,Key:string):string;
begin
   Result:=EncryStrhex(MimeEncodeString(str),key);  //加密
end;

Function My_Decode(str,Key:string):string;
begin
  result:=MimeDecodeString(DecryStrHex(str,key)); //解密
end;

end.