desunit.pas

一套完整的软件保护示例 ├──Check..............软件保护示例 └──KeyGen.............注册机制作示例

unit DESUnit;

interface

uses SysUtils;

type
  TKeyByte = array[0..5] of Byte;
  TDesMode = (dmEncry, dmDecry);

  function DESEncrypt(Input, Key: String): String;
  function DESDecrypt(Input, Key: String): String;

var
  subKey: array[0..15] of TKeyByte;
      
implementation

{$I SBox.inc}

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);
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];
      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
  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 DESEncrypt(Input, Key: String): String;
var
  StrResult, TempResult, Temp: String;
  I: Integer;
begin
  TempResult := EncryStr(Input, 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 DESDecrypt(Input, 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(Input) div 2 - 1 do
  begin
    Temp := Copy(Input, I * 2 + 1, 2);
    Str := Str + Chr(HexToInt(Temp));
  end;
  Result := DecryStr(Str, Key);
end;

end.