//******************************************************************************
//基于MD5算法的Hash MAC：应用

//******************************************************************************
//作者：Cai
//日期：2011-10-25
//******************************************************************************

unit HMAC_MD5Utils;


interface
uses
SysUtils, Classes,
HMAC_MD5Class, MD5Class;

type


THMAC_MD5 = class
protected
   FHMAC: THMAC_MD5Class;
public
   constructor Create(); virtual;
   destructor Destroy; override;
   //=========基于MD5的Hash MAC算法：应用==========
   function HMAC_StrToMD5_String(sStr: string; sKey: string): string;
   function HMAC_StrToMD5_Digest(sStr: string; sKey: string): TMD5Digest;
   function HMAC_FileToMD5_String(sFileName: string; sKey: string): string;
   function HMAC_FileToMD5_Digest(sFileName: string; sKey: string): TMD5Digest; 
end;

implementation



{ THMAC_MD5 }

constructor THMAC_MD5.Create;
begin
   FHMAC:=THMAC_MD5Class.Create();
end;

destructor THMAC_MD5.Destroy;
begin
   FHMAC.Destroy;
   inherited;
end;

function THMAC_MD5.HMAC_FileToMD5_Digest(sFileName,
sKey: string): TMD5Digest;
var
   FileStream: TFileStream;
   iLen: UINT4;
   Buffer: array[0..1024-1]of Byte;
   Context: THMAC_MD5Context;
begin
   FillChar(Result, SizeOf(TMD5Digest), 0);
   if not FileExists(sFileName) then Exit;
   FileStream := TFileStream.Create(sFileName, fmOpenRead or fmShareDenyNone);
   try
   FHMAC.HMAC_MD5Init(Context, sKey);
   while True do
   begin
     iLen := FileStream.Read(Buffer, 1024);
     if iLen>0 then
       FHMAC.HMAC_MD5Update(Context, @Buffer, iLen);
     if iLen<1024 then Break;
   end;
   FHMAC.HMAC_MD5Final(Result, Context);
   finally
     FileStream.Destroy;
   end;
end;

function THMAC_MD5.HMAC_FileToMD5_String(sFileName, sKey: string): string;
begin
   Result := TMD5Class.DigestToString(HMAC_FileToMD5_Digest(sFileName, sKey));
end;

function THMAC_MD5.HMAC_StrToMD5_Digest(sStr, sKey: string): TMD5Digest;
var
Context: THMAC_MD5Context;
begin
   FillChar(Result, SizeOf(TMD5Digest), 0);
   FHMAC.HMAC_MD5Init(Context, sKey);
   FHMAC.HMAC_MD5Update(Context, PByte(PChar(sStr)), Length(sStr));
   FHMAC.HMAC_MD5Final(Result, Context);
end;

function THMAC_MD5.HMAC_StrToMD5_String(sStr, sKey: string): string;
begin
   Result := TMD5Class.DigestToString(HMAC_StrToMD5_Digest(sStr, sKey));
end;

end. 

// ==========================================

//测试代码;

unit Unit1;

interface

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

type
TForm1 = class(TForm)
   Edit1: TEdit;
   Memo1: TMemo;
   Button1: TButton;
   Button2: TButton;
   OpenDialog1: TOpenDialog;

   Edit2: TEdit;
   procedure Button1Click(Sender: TObject);
   procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation
uses
HMAC_MD5Utils;

{$R *.dfm}

var   
HMAC_MD5: THMAC_MD5;

procedure TForm1.Button1Click(Sender: TObject);
begin
  HMAC_MD5:=THMAC_MD5.Create;
  try
    Memo1.Lines.Add('Text HMAC_MD5 = '+HMAC_MD5.HMAC_StrToMD5_String(Edit1.Text, Edit2.Text));
  finally
    HMAC_MD5.Destroy;
  end;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  if not OpenDialog1.Execute() then Exit;
  HMAC_MD5:=THMAC_MD5.Create;
  try
    Memo1.Lines.Add('File HMAC_MD5 = '+HMAC_MD5.HMAC_FileToMD5_String(OpenDialog1.FileName, Edit2.Text));
  finally
    HMAC_MD5.Destroy;
  end;
end;

end.