uencrypt.pas

对字符串等如string的加密和解密 加密和解密 加密和解密

unit uEncrypt;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ComCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    RichEdit1: TRichEdit;
    Button2: TButton;
    OpenDialog1: TOpenDialog;
    Button3: TButton;
    Button4: TButton;
    SaveDialog1: TSaveDialog;
    procedure Button2Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
   function Decrypt(const S: AnsiString; Key: Word): AnsiString;
   function Encrypt(const S: AnsiString; Key: Word): AnsiString;
  end;

var
  Form1: TForm1;
const
  C1 = 52845;
  C2 = 22719;
implementation

{$R *.dfm}
function Decode(const S: AnsiString): AnsiString;
const
  Map: array[Char] of Byte = (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 62, 0, 0, 0, 63, 52, 53,
    54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2,
    3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
    20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 0, 0, 26, 27, 28, 29, 30,
    31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45,
    46, 47, 48, 49, 50, 51, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0);
var
  I: LongInt;
begin
  case Length(S) of
    2:
      begin
        I := Map[S[1]] + (Map[S[2]] shl 6);
        SetLength(Result, 1);
        Move(I, Result[1], Length(Result))
      end;
    3:
      begin
        I := Map[S[1]] + (Map[S[2]] shl 6) + (Map[S[3]] shl 12);
        SetLength(Result, 2);
        Move(I, Result[1], Length(Result))
      end;
    4:
      begin
        I := Map[S[1]] + (Map[S[2]] shl 6) + (Map[S[3]] shl 12) +
          (Map[S[4]] shl 18);
        SetLength(Result, 3);
        Move(I, Result[1], Length(Result))
      end
  end
end;

function PreProcess(const S: AnsiString): AnsiString;
var
  SS: AnsiString;
begin
  SS := S;
  Result := '';
  while SS <> '' do
  begin
    Result := Result + Decode(Copy(SS, 1, 4));
    Delete(SS, 1, 4)
  end
end;

function InternalDecrypt(const S: AnsiString; Key: Word): AnsiString;
var
  I: Word;
  Seed: Word;
begin
  Result := S;
  Seed := Key;
  for I := 1 to Length(Result) do
  begin
    Result[I] := Char(Byte(Result[I]) xor (Seed shr 8));
    Seed := (Byte(S[I]) + Seed) * Word(C1) + Word(C2)
  end
end;

procedure TForm1.Button2Click(Sender: TObject);
const
 my_key = 33189;
var
  sDecrypted :AnsiString;
  str:string;
begin
   richedit1.SelectAll;
   str:=richedit1.SelText;
   sDecrypted := Decrypt(str,my_key);
   richedit1.Clear;
   richedit1.Lines.Add(sDecrypted);

end;

procedure TForm1.Button3Click(Sender: TObject);
begin
if OpenDialog1.Execute then
    RichEdit1.Lines.LoadFromFile(OpenDialog1.FileName);
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
 if SaveDialog1.Execute then
 RichEdit1.Lines.SaveToFile(SaveDialog1.FileName);
end;

function TForm1.Decrypt(const S: AnsiString; Key: Word): AnsiString;
begin
  Result := InternalDecrypt(PreProcess(S), Key)
end;

function Encode(const S: AnsiString): AnsiString;
const
  Map: array[0..63] of Char = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' +
    'abcdefghijklmnopqrstuvwxyz0123456789+/';
var
  I: LongInt;
begin
  I := 0;
  Move(S[1], I, Length(S));
  case Length(S) of
    1:
      Result := Map[I mod 64] + Map[(I shr 6) mod 64];
    2:
      Result := Map[I mod 64] + Map[(I shr 6) mod 64] +
        Map[(I shr 12) mod 64];
    3:
      Result := Map[I mod 64] + Map[(I shr 6) mod 64] +
        Map[(I shr 12) mod 64] + Map[(I shr 18) mod 64]
  end
end;

function PostProcess(const S: AnsiString): AnsiString;
var
  SS: AnsiString;
begin
  SS := S;
  Result := '';
  while SS <> '' do
  begin
    Result := Result + Encode(Copy(SS, 1, 3));
    Delete(SS, 1, 3)
  end
end;

function InternalEncrypt(const S: AnsiString; Key: Word): AnsiString;
var
  I: Word;
  Seed: Word;
begin
  Result := S;
  Seed := Key;
  for I := 1 to Length(Result) do
  begin
    Result[I] := Char(Byte(Result[I]) xor (Seed shr 8));
    Seed := (Byte(Result[I]) + Seed) * Word(C1) + Word(C2)
  end
end;

function TForm1.Encrypt(const S: AnsiString; Key: Word): AnsiString;
begin
  Result := PostProcess(InternalEncrypt(S, Key))
end;



procedure TForm1.Button1Click(Sender: TObject);
const
 my_key = 33189;
var
  sEncrypted, sDecrypted :AnsiString;
  str:string;
begin
   richedit1.SelectAll;
   str:=richedit1.SelText;
   sEncrypted := Encrypt(str,my_key);
   richedit1.Clear;
   richedit1.Lines.Add(sEncrypted);
  // 加密
//  sEncrypted := Encrypt('this is a sample text to encrypt...abcd 123 {}[]?=)=(',my_key);
  //显示加密后字符串
//  ShowMessage(sEncrypted);
  //解密
//  sDecrypted := Decrypt(sEncrypted,my_key);
   // 显示解密后字符串
//  ShowMessage(sDecrypted);
end;


end.