asked on

Using function from DLLs (crypt32.dll) in Delphi

Hi,

Crypt32.dll has a function named CryptProtectData. I would like to use that function to encrypt something. But I have no idea how.

In Visual Basic, you'd use something like:

---

Private Declare Function CryptProtectData Lib "crypt32.dll" (ByRef r_udtDataIn As DATA_BLOB, ByVal v_sDataDescr As String, ByRef r_anyOptionalEntropy As Any, ByRef r_anyReserved As Any, ByRef r_anyPromptStruct As Any, ByVal v_lFlags As Long, ByRef r_udtDataOut As DATA_BLOB) As Long

Dim udtDataOut As DATA_BLOB
Dim udtDataIn As DATA_BLOB

Call CryptProtectData(udtDataIn, "", ByVal vbNullString, ByVal vbNullString, ByVal vbNullString, 0, udtDataOut)

---

But what to do in Delphi? Anyone any idea how to get the result?

Mike Littlewood

It would be something along the lines of the function below but Im not sure of the parameters DATA_BLOB

function CryptProtectData(r_udtDataIn: Variant; v_sDataDescr: String; r_anyOptionalEntropy: Variant; r_anyReserved: Variant; r_anyPromptStruct: Variant; v_lFlags: Integer; r_udtDataOut: Variant): Integer; external 'Crypt32.dll' name 'CryptProtectData';

TonyJix

ASKER

Thank you for the reply - I already figured it'd be something like that but I am not able to get it to return anything.

On this site you see official information on function CryptProtectData:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/seccrypto/security/cryptprotectdata.asp

It also has link with more information about the DATA_BLOB type. But im not experienced enough to do something with that info.

As far as I can tell regarding the parameters, all of them may be empty, except the first one (data in).
"Data in" variable is some text encoded to base64. But that's not the probem really. First I need to know
how to even use this function and get any result.

Thank you to anyone in advance.

TonyJix

ASKER

Ok I figured out the DATA_BLOB variables and everything.

I am ready to run the function, but it gives me an error when I use it:

It says Access Violation.

Any idea?

Greeting,

Russell Libby

The correct definitions are listed below. If you have problems with the correct defines, I would need to see a code clip of what you are trying to do.

Regards,
Russell

type
TLargeByteArray = Array [0..Pred(MaxInt)] of Byte;
PLargeByteArray = ^TLargeByteArray;

type
_CRYPTOAPI_BLOB = packed record
cbData: DWORD;
pbData: PLargeByteArray;
end;
TCryptoApiBlob = _CRYPTOAPI_BLOB;
PCrypyoApiBlob = ^TCryptoApiBlob;
CRYPT_INTEGER_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_INTEGER_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_UINT_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_UINT_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_OBJID_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_OBJID_BLOB = ^CRYPT_INTEGER_BLOB;
CERT_NAME_BLOB = _CRYPTOAPI_BLOB;
PCERT_NAME_BLOB = ^CRYPT_INTEGER_BLOB;
CERT_RDN_VALUE_BLOB = _CRYPTOAPI_BLOB;
PCERT_RDN_VALUE_BLOB = ^CRYPT_INTEGER_BLOB;
CERT_BLOB = _CRYPTOAPI_BLOB;
PCERT_BLOB = ^CRYPT_INTEGER_BLOB;
CRL_BLOB = _CRYPTOAPI_BLOB;
PCRL_BLOB = ^CRYPT_INTEGER_BLOB;
DATA_BLOB = _CRYPTOAPI_BLOB;
PDATA_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_DATA_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_DATA_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_HASH_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_HASH_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_DIGEST_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_DIGEST_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_DER_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_DER_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_ATTR_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_ATTR_BLOB = ^CRYPT_INTEGER_BLOB;

type
_CRYPTPROTECT_PROMPTSTRUCT = packed record
cbSize: DWORD;
dwPromptFlags: DWORD;
hwndApp: HWND;
szPrompt: LPCWSTR;
end;
TCryptProtectPromptStruct = _CRYPTPROTECT_PROMPTSTRUCT;
PCryptProtectPromptStruct = ^TCryptProtectPromptStruct;
CRYPTPROTECT_PROMPTSTRUCT = _CRYPTPROTECT_PROMPTSTRUCT;
PCRYPTPROTECT_PROMPTSTRUCT = ^_CRYPTPROTECT_PROMPTSTRUCT;

function CryptProtectData(pDataIn: PDATA_BLOB;
szDataDescr: LPCWSTR {PWideChar};
pOptionalEntropy: PDATA_BLOB;
pReserved: Pointer;
pPromptStruct: PCRYPTPROTECT_PROMPTSTRUCT;
dwFlags: DWORD;
pDataOut: PDATA_BLOB): BOOL; stdcall; external 'Crypt32.dll';

TonyJix

ASKER

Hi,

thank you.. I guess it's like that.
Still when I call it, I get an access error.

Im just not able to get this stuff working, it's frustrating.

I have the full source of this program in Visual Basic where it all looks so easy to call the function, but it is just impossible in Delphi.
What CryptProtectData does is it accepts a string and then encrypts it and returns something.
This string is base64 encoded and then put into a Byte Array.
The PData_Blob variable is simply some kind of variable with 2 parts: one sets a length and second is a pointer to an array.
the Data_Blob variable is defined in WinCrypt.pas - a port from WinCrypt.H

Do you know Visual Basic? I'd pay $100 to anyone who could translate not even 10 lines of code into Delphi.

I appreciate the replies ;-)

Russell Libby

First, to address the following:

>> thank you.. I guess it's like that.

Let me be clear.... it *IS*like that.

The "As Any" in VB translates to a pointer type declaration in C/C++/Delphi, not a variant like you had above. The stdcall was also missing on the function. And the second param, which is a PWideChar desc is required (null cannot be passed). I also know how the API works, and it doesn't require a base64 encoded string; the data can be anything you want, plaintext or otherwise. I also gave you the DATA_BLOB (and other) structure defs, so I am not sure why you are describing these things to me? And yes I know VB (and a half dozen other langs), but you don't need to pay anyone to do this for you, you just need to post the code to be translated, which is why I wrote:

>> I would need to see a code clip of what you are trying to do.

Which you did not provide. The only thing I can do at this point is to provide a Delphi example of both the en/decrypt functions. If you wish to provide the VB code, then I can help further.

Russell

---

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

type
TLargeByteArray = Array [0..Pred(MaxInt)] of Byte;
PLargeByteArray = ^TLargeByteArray;

type
_CRYPTOAPI_BLOB = packed record
cbData: DWORD;
pbData: PLargeByteArray;
end;
TCryptoApiBlob = _CRYPTOAPI_BLOB;
PCrypyoApiBlob = ^TCryptoApiBlob;
CRYPT_INTEGER_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_INTEGER_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_UINT_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_UINT_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_OBJID_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_OBJID_BLOB = ^CRYPT_INTEGER_BLOB;
CERT_NAME_BLOB = _CRYPTOAPI_BLOB;
PCERT_NAME_BLOB = ^CRYPT_INTEGER_BLOB;
CERT_RDN_VALUE_BLOB = _CRYPTOAPI_BLOB;
PCERT_RDN_VALUE_BLOB = ^CRYPT_INTEGER_BLOB;
CERT_BLOB = _CRYPTOAPI_BLOB;
PCERT_BLOB = ^CRYPT_INTEGER_BLOB;
CRL_BLOB = _CRYPTOAPI_BLOB;
PCRL_BLOB = ^CRYPT_INTEGER_BLOB;
DATA_BLOB = _CRYPTOAPI_BLOB;
PDATA_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_DATA_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_DATA_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_HASH_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_HASH_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_DIGEST_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_DIGEST_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_DER_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_DER_BLOB = ^CRYPT_INTEGER_BLOB;
CRYPT_ATTR_BLOB = _CRYPTOAPI_BLOB;
PCRYPT_ATTR_BLOB = ^CRYPT_INTEGER_BLOB;

type
_CRYPTPROTECT_PROMPTSTRUCT = packed record
cbSize: DWORD;
dwPromptFlags: DWORD;
hwndApp: HWND;
szPrompt: LPCWSTR;
end;
TCryptProtectPromptStruct = _CRYPTPROTECT_PROMPTSTRUCT;
PCryptProtectPromptStruct = ^TCryptProtectPromptStruct;
CRYPTPROTECT_PROMPTSTRUCT = _CRYPTPROTECT_PROMPTSTRUCT;
PCRYPTPROTECT_PROMPTSTRUCT = ^_CRYPTPROTECT_PROMPTSTRUCT;

function CryptProtectData(pDataIn: PDATA_BLOB;
szDataDescr: LPCWSTR {PWideChar};
pOptionalEntropy: PDATA_BLOB;
pReserved: Pointer;
pPromptStruct: PCRYPTPROTECT_PROMPTSTRUCT;
dwFlags: DWORD;
pDataOut: PDATA_BLOB): BOOL; stdcall; external 'Crypt32.dll';

function CryptUnprotectData(pDataIn: PDATA_BLOB;
var ppszDataDescr:LPWSTR;
pOptionalEntropy: PDATA_BLOB;
pReserved: Pointer;
pPromptStruct: PCRYPTPROTECT_PROMPTSTRUCT;
dwFlags: DWORD;
pDataOut: PDATA_BLOB): BOOL; stdcall; external 'Crypt32.dll';

implementation
{$R *.DFM}

// Helper functions for dealing with the blob structs
procedure FreeDataBlob(var Data: DATA_BLOB);
begin

// Check pointer to data
if Assigned(Data.pbData) then LocalFree(HLOCAL(Data.pbData));

// Clear struct
FillChar(Data, SizeOf(DATA_BLOB), 0);

end;

function GetDataBlobText(Data: DATA_BLOB): String;
begin

// Check blob pointer
if (Data.cbData > 0) and Assigned(Data.pbData) then
// Set result string
SetString(result, PChar(Data.pbData), Data.cbData)
else
// Set null result
SetLength(result, 0);

end;

function SetDataBlobText(Text: String; var Data: DATA_BLOB): Boolean;
begin

// Clear struct
FillChar(Data, SizeOf(DATA_BLOB), 0);

// Check passed text
if (Length(Text) > 0) then
begin
// Allocate memory for text
Data.pbData:=Pointer(LocalAlloc(LPTR, Succ(Length(Text))));
// Check pointer
if Assigned(Data.pbData) then
begin
// Copy data
StrPCopy(PChar(Data.pbData), Text);
// Set buffer length
Data.cbData:=Length(Text);
// Success
result:=True;
end
else
// Failed to allocate memory
result:=False;
end
else
// Nothing to copy over
result:=True;

end;

// Encrypt and decrypt some data
procedure TForm1.Button1Click(Sender: TObject);
var DataIn: DATA_BLOB;
DataOut: DATA_BLOB;
DataCheck: DATA_BLOB;
lpwszDesc: PWideChar;
begin

// Clear structs
FillChar(DataIn, SizeOf(DATA_BLOB), 0);
FillChar(DataOut, SizeOf(DATA_BLOB), 0);
FillChar(DataCheck, SizeOf(DATA_BLOB), 0);

// Set text to be encrypted
if SetDataBlobText('Hello world this is a test!', DataIn) then
begin
// Resource protection
try
// Encrypt the data. NOTE: The description is REQUIRED and cannot be NULL per MSDN
if CryptProtectData(@DataIn, PWideChar(WideString('Hello Test')), nil, nil, nil, 0, @DataOut) then
begin
// Display the encrypted data
MessageBox(0, PChar(GetDataBlobText(DataOut)), PChar(Format('%d bytes returned', [DataOut.cbData])), MB_OK or MB_ICONINFORMATION);
// Resource protection
try
// Unencrypt the data
if CryptUnprotectData(@DataOut, lpwszDesc, nil, nil, nil, 0, @DataCheck) then
begin
// Resource protection
try
// Display unencrypted text
MessageBox(0, PChar(GetDataBlobText(DataCheck)), PChar(String(WideString(lpwszDesc))), MB_OK or MB_ICONINFORMATION);
finally
// Clean up memory
LocalFree(HLOCAL(lpwszDesc));
FreeDataBlob(DataCheck);
end;
end;
finally
// Clean up memory
FreeDataBlob(DataIn);
end;
end;
finally
// Clean up memory
FreeDataBlob(DataIn);
end;
end;

end;

end.

TonyJiz

Russell,

You are definitely right. Sorry, I think I misunderstood you.

Your example is pretty much all I need. But if you are able to convert this VbCode (which should be easy since you know both well), then it's done:

-- Main --

Dim sUser As String
Dim sVal As String

sUser = Text1.Text 'Get the input (email address), for example: johnny@johnny.com

sVal = StdEncrypt(sUser & Chr$(0)) 'Do the encryption, see this function below

BinaryValue(HKEY_CURRENT_USER, "Software\Program", "Result") = StrConv(sVal, vbFromUnicode) 'Write result as Binary to Key

-- StdEncrypt Function --

Public Function StdEncrypt(ByRef r_sData As String) As String

Dim abytFileData() As Byte
Dim abytDataOut() As Byte
Dim udtDataOut As DATA_BLOB
Dim udtDataIn As DATA_BLOB
Dim udtPw As DATA_BLOB
Dim iFile As Integer
Dim sData As String

sData = Base64_Encode(r_sData)

If isNTKernel Then
abytFileData = StrConv(sData, vbFromUnicode) & Chr$(0)
MsgBox (abytFileData(1))
udtDataIn.cbData = UBound(abytFileData) + 1
udtDataIn.pbData = VarPtr(abytFileData(0))

Call CryptProtectData(udtDataIn, "", ByVal vbNullString, ByVal vbNullString, ByVal vbNullString, 0, udtDataOut)

ReDim abytDataOut(udtDataOut.cbData) As Byte
Call CopyMemory(abytDataOut(0), ByVal udtDataOut.pbData, udtDataOut.cbData)
StdEncrypt = Chr$(3) & Chr$(4) & StrConv(abytDataOut, vbUnicode)

Else
StdEncrypt = sData

End If

End Function

---

That's it. So the result of all this is a Binary entry written to the Registry.
I would so appreciate it if you could translate the above code in Delphi.

Thank you alot,

TonyJiz

Regarding the Base64 encode function that it calls...
I compared the result with Mime::Base64 module in Perl, and it's the same result. So it's really only encoding to Base64 in that function and not doing anything else with it.

Russell Libby

Its going to take me some time (2 hours) to gve you a translation that captures the "true intent" of the above code, so please be patient. The above code is meant to work on all Win9X/NT based systems, so late binding is going to be required. And the encoding to Base64 is used as the "encryption" when running on systems less than Win2K (a check for NT is not enough). To be honest, the VB code listed above is extremely prone to errors, which is why I need a little bit of time to provide a clean/working example.

Regards,
Russell

TonyJix

ASKER

I really appreciate your efforts!

I'm looking forward to the code, and please don't forget to include your paypal address since this solution is worth more than 500 points to me.

Thank you!

ASKER CERTIFIED SOLUTION

Russell Libby

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TonyJix

ASKER

Absolutely superb. I have nothing else to say about this quality stuff.

You have no idea how much you helped me. Thank you very much. Great stuff.

Russell Libby

Very glad to have helped,
Russell