unit MSNId2_V2;

interface

Uses SysUtils, Windows, Classes;

Type
    TMSN_Id2File = Class(TObject)
    Private
      _hKey : ULong;
      _hHash : ULong;
      _hProvider : ULong;
      Procedure ReleaseKey;
      Function UpdateKey(szKey : String) : Boolean;
    Public
      Constructor Create;
      Destructor Destroy; Override;
      Function Decrypt(szKey : String; AStream : TStream) : Boolean;
    End;

implementation

Uses Dialogs;

Function CryptDestroyKey(hKey : ULong) : Bool; Stdcall; External 'advapi32.dll';
Function CryptDestroyHash(hHash : Ulong) : Bool; Stdcall; External 'advapi32.dll';
Function CryptReleaseContext(hProv : ULong; dwFlags : DWORD) : Bool; Stdcall; External 'advapi32.dll';
Function CryptAcquireContext(VAR phProv : ULong; pszContainer, pszProvider : PCHAR;
         dwProvType, dwFlags : DWORD) : Bool; Stdcall; External 'advapi32.dll' Name 'CryptAcquireContextA';
Function CryptCreateHash(hProv : ULong; algid : UInt; hKey : ULong; dwFlags : DWORD; VAR phHash : ULong) : Bool; Stdcall; External 'advapi32.dll';
Function CryptHashData(hHash : ULong; pbData : PChar; dwDataLen, dwFlags : DWORD) : Bool; Stdcall; External 'advapi32.dll';
Function CryptDeriveKey(hProv : ULong; algid : UInt; hBaseData : ULong; dwFlags : DWORD; VAR phKey : ULong) : Bool; Stdcall; External 'advapi32.dll';
Function CryptDecrypt(hKey, hHash : ULong; Final : Boolean; dwFlags : ULong; VAR pData; Var pdwDataLen : ULong) : Bool; Stdcall; External 'advapi32.dll';

Const
     PROV_RSA_AES = 24;
     CRYPT_NEWKEYSET = 8;
     CRYPT_EXPORTABLE = 1;

     ALG_CLASS_HASH = 32768;
     ALG_TYPE_ANY = 0;
     ALG_SID_SHA1 = 4;
     CALG_SHA1 = ALG_CLASS_HASH Or ALG_TYPE_ANY Or ALG_SID_SHA1;

     ALG_CLASS_DATA_ENCRYPT = 24576;
     ALG_TYPE_BLOCK = 1536;
     ALG_SID_AES_128 = 14;
     CALG_AES_128 = ALG_CLASS_DATA_ENCRYPT Or ALG_TYPE_BLOCK Or ALG_SID_AES_128;

{==============================================================================}
{  TMSN_Id2File :: Constructor / Destructor  }
{==============================================================================}

Constructor TMSN_Id2File.Create;
Begin
Inherited Create;
End;

{==============================================================================}
{==============================================================================}

Destructor TMSN_Id2File.Destroy;
Begin
Inherited Destroy;
End;

{==============================================================================}
{  TMSN_Id2File :: Methodes Privees  }
{==============================================================================}

Procedure TMSN_Id2File.ReleaseKey;
Begin
If Self._hKey > 0 Then
   Begin
   CryptDestroyKey(Self._hKey);
   Self._hKey := 0;
   End;

If Self._hHash > 0 Then
   Begin
   CryptDestroyHash(_hHash);
   Self._hHash := 0;
   End;

If Self._hProvider > 0 Then
   Begin
   CryptReleaseContext(_hProvider, 0);
   Self._hProvider := 0;
   End;
End;

{==============================================================================}
{==============================================================================}

Function TMSN_Id2File.UpdateKey(szKey : String) : Boolean;
Begin
Result := False;
If Length(szKey) <> 16 Then Exit;

Self.ReleaseKey;
szKey := Lowercase(szKey);

//ShowMEssage(IntToStr(Self._hProvider));
//ShowMEssage(IntToStr(Self._hHash));
//ShowMEssage(IntToStr(Self._hKey));

If not CryptAcquireContext(Self._hProvider, nil, nil, PROV_RSA_AES, 0) Then
   If not CryptAcquireContext(_hProvider, nil, nil, PROV_RSA_AES, CRYPT_NEWKEYSET) Then Exit;

If CryptCreateHash(Self._hProvider, CALG_SHA1, 0, 0, Self._hHash) Then
   If CryptHashData(Self._hHash, PChar(szKey), Length(szKey) * 2, 0) Then
      If CryptDeriveKey(Self._hProvider, CALG_AES_128, Self._hHash, CRYPT_EXPORTABLE, Self._hKey) Then
         Result := True;

//ShowMEssage(IntToStr(Self._hProvider));
//ShowMEssage(IntToStr(Self._hHash));
//ShowMEssage(IntToStr(Self._hKey));
End;

{==============================================================================}
{  TMSN_Id2File :: Methode Publique  }
{==============================================================================}

Function TMSN_Id2File.Decrypt(szKey : String; AStream : TStream) : Boolean;
Var Data : array of Byte;
    Size, Count : DWord;
    F : File;
    Err, i : Integer;
Begin
Result := False;

If not Self.UpdateKey(szKey) Then Exit;

If not Assigned(AStream) Then ShowMEssage('Erreur Stream');

Size := AStream.Size;
SetLEngth(data, Size);
AStream.Position := 0;
For i := 0 to Size-1 do
    AStream.Read(data[i], 1);

ShowMessage('ok');

CryptDecrypt(Self._hKey, 0, True, 0, data, Size);
Err := GetLastError;
ShowMEssage(IntToStr(err));
Case Err of
     ERROR_INVALID_HANDLE : ShowMessage('ERROR_INVALID_HANDLE');
     ERROR_INVALID_PARAMETER : ShowMessage('ERROR_INVALID_PARAMETER');
     NTE_BAD_ALGID : ShowMessage('NTE_BAD_ALGID');
     NTE_BAD_DATA : ShowMessage('NTE_BAD_DATA');
     NTE_BAD_FLAGS : ShowMessage('NTE_BAD_FLAGS');
     NTE_BAD_HASH : ShowMessage('NTE_BAD_HASH');
     NTE_BAD_KEY : ShowMessage('NTE_BAD_KEY');
     NTE_BAD_LEN : ShowMessage('NTE_BAD_LEN');
     NTE_BAD_UID : ShowMessage('NTE_BAD_UID');
     NTE_DOUBLE_ENCRYPT : ShowMessage('NTE_DOUBLE_ENCRYPT');
     NTE_FAIL : ShowMessage('NTE_FAIL');
     end;
//If not CryptDecrypt(Self._hKey, 0, True, 0, data, Size) Then
//   Begin ShowMEssage('Erreur Decryptage'); Exit; End;

//AStream.Position := 0;
//AStream.Size := 0;
//AStream.Write(data^, size);

//ShowMEssage('Decryptage terminé');
End;



end.