delphi 字符串16进制转换后加密

function GetStreamString( stream:TStream ):string;   //函数不需要声明和应用
var
strStream:TStringStream;
begin
strStream:= TStringStream.Create( ' ' );
try
strStream.CopyFrom( stream, stream.Size );
Result:=strStream.DataString;
finally
strStream.Free;
end;
end;

function myStrToHex(s:string):string; //字串转16进制
var
  TmpStr:string;
  i:integer;
begin
  TmpStr:='';
  for i:=1 to Length(s)do
    TmpStr:=TmpStr+IntToHex(ord(s[i]),2);  
  Result:=TmpStr;  
end;  
  
function myHexToStr(S:string):string; //16进制转字串
var  
  HexS,TmpStr:string;  
  i:Integer;  
  a:Byte;  
begin  
  HexS:=s;
  if Length(HexS) mod 2=1 then  
    HexS:=HexS+'0';
  TmpStr:='';  
  for i:=1 to(Length(HexS)div 2)do  
  begin  
    a:=StrToInt('$'+HexS[2*i-1]+HexS[2*i]);  
    TmpStr:=TmpStr+Chr(a);  
  end;
  Result:=TmpStr;  
end; 


{两个函数的参数相同，s为要加密、解密的字串；sKey为密匙}  
function EncryptStr(const s:string;sKey:string):string; //加密   
var  
  i,j:Integer;
  HexS,HexsKey,MidS,TmpStr:string;  
  a,b,c:byte;  
begin  
  HexS:=myStrToHex(s);  
  HexsKey:=myStrToHex(sKey);  
  MidS:=HexS;  
  for i:=1 to(Length(HexsKey)div 2)do  
  begin  
    if i<>1 then MidS:=TmpStr;
    TmpStr:=''; //下面要用到TmpStr，所以要清空   
    for j:=1 to (Length(MidS)div 2)do  
    begin  
      a:=StrToInt('$'+midS[2*j-1]+midS[2*j]);  
      b:=StrToInt('$'+HexsKey[2*i-1]+HexsKey[2*i]);  
      c:=a xor b;  
      tmpstr:=TmpStr+myStrToHex(Chr(c));  
    end;  
  end;
  Result:=TmpStr;  
end;  
  
function DecryptStr(const s:string;sKey:string):string; //解密   
var  
  i,j:Integer;  
  HexS,HexsKey,MidS,TmpStr:string;  
  a,b,c:Byte;  
begin  
  HexS:=s;
  if Length(HexS)mod 2=1 then //检查是否为字符串   
  begin  
    ShowMessage('密文错误！');  
    Exit;  
  end;  
  HexsKey:=myStrToHex(sKey);  
  TmpStr:=HexS;  
  MidS:=HexS;  
  for i:=(length(HexsKey) div 2) downto 1 do  
  begin  
    if i<>(length(HexsKey) div 2)then
      MidS:=TmpStr;  
    TmpStr:=''; //下面要用到TmpStr，所以要清空   
    for j:=1 to(length(MidS) div 2)do  
    begin  
      a:=StrToInt('$'+MidS[2*j-1]+MidS[2*j]);  
      b:=StrToInt('$'+HexsKey[2*i-1]+HexsKey[2*i]);  
      c:=a xor b;  
      TmpStr := TmpStr+myStrToHex(Chr(c));  
    end;  
  end;  
    Result:=myHexToStr(TmpStr);
end;  


procedure TForm1.Button1Click(Sender: TObject);
var
t : TFileStream;
s : String;
i : Int64;
begin
t := TFileStream.Create( 'c:\1.txt ', fmOpenRead);
try
i := t.Size;
SetLength(s, i);
t.ReadBuffer(s[1], i);
ShowMessage (s);
finally
t.Free;
end;
end;


procedure TForm1.Button2Click(Sender: TObject);
begin
     //EncryStrHex('1','2');
     //delphi 对字符串进行加密实现,字符串转16进制，然后再加密
        Edit1.Text:=DecryptStr(Edit1.Text,'delphi');
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
     Edit1.Text:=EncryptStr('Hello','delph2i');
     //hello为加密的明文，delphi密钥，密钥不同就无法解密
end;