C / C++ / MFC Discussion Boards

Re: Encrypt text using java and decrypt using C

Niklas L16-Jun-10 20:39

Niklas L

16-Jun-10 20:39

Is your third point some kind of recursive definition? Poke tongue | ;-P

home

Re: Encrypt text using java and decrypt using C

Moak17-Jun-10 10:49

Moak

17-Jun-10 10:49

Nice trick there from Cedric! Smile | :)

Chat in Europe Java | [Coffee]

Now with 24% more Twitter

Re: Encrypt text using java and decrypt using C

Niklas L17-Jun-10 11:18

Niklas L

17-Jun-10 11:18

Yeah, took me about 15 minutes before I realized I was reading the same row over and over... (cheeky bastard) Laugh | :laugh:

home

Re: Encrypt text using java and decrypt using C

Aescleal16-Jun-10 22:43

Aescleal

16-Jun-10 22:43

Have a look at OpenSSL. It supports AES and you should be able to use if from Java and C. If you have problems using it from C then feel free to ask questions about how to use it. I believe there's a JNI wrapper for it as well to save you rolling your own but I've never used it.

Oh, and if you do a search for "Gladman" and "AES" you might find another open source implementation of AES. I've never used it but one of my co-workers does in a product. It's lighter weight than OpenSSL and you should be able to compile and link it with your C code.

Cheers,

Ash

Re: Encrypt text using java and decrypt using C

ThatsAlok16-Jun-10 23:54

ThatsAlok

16-Jun-10 23:54

Murugan k wrote:
I need to encrypt the plan text using AES algorithm in java and decrypt the encrypted text using C.Any please give solution ASAP.

do you know how to write AES alogorithm in C and Java

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture

cheers,
Alok Gupta
VC Forum Q&A :- I/IV
Support CRY- Child Relief and You

Re: Encrypt text using java and decrypt using C

Aescleal18-Jun-10 9:23

Aescleal

18-Jun-10 9:23

Have a look at Brian Gladman's implementation. That shows you in balls-aching detail how to implement AES. If I were you I'd just use his or the one in OpenSSL.

Cheers,

Ash

CClientDc

VVVimal16-Jun-10 18:39

VVVimal

16-Jun-10 18:39

Hi
I am using CClientDc in OnTimer().

Sample Code:
OnTimer()
{
CClientDc dc;
DisplayAll(dc,xCor,Ycor);
Release(&dc);
}
But When run the program through the Deleaker
I am getting GDI leak in this part. I am not sure weather the CClientDc is released. Also my applicatin size increases continously. Pls help to resolve this problem.

Re: CClientDc

«_Superman_»16-Jun-10 18:54

«_Superman_»

16-Jun-10 18:54

You do not have to call Release.
The destructor of CClientDC will do that when it goes out of scope.

The leak is probably because of something that is happening inside the DisplayAll function.

«_Superman_»

I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

Re: CClientDc

Stephen Hewitt16-Jun-10 19:23

Stephen Hewitt

16-Jun-10 19:23

«_Superman_» is correct: First lose the Release and see if commenting out DisplayAll stops the leaks. If it does one sledgehammer approach is comment bits of the function out bit by bit until you find the problem.

Steve

Re: CClientDc

Aescleal16-Jun-10 22:50

Aescleal

16-Jun-10 22:50

Get rid of all drawing code in your OnTimer. Make sure OnPaint does all the
drawing correctly and then replace all the code in OnTimer with:

Invalidate();

That'll help sort out whether the problem is with the drawing code or whether you're committing another faux pas.

In case you're wondering Invalidate tells Windows that the window you've called it on needs repainting and it should send a WM_PAINT to the app when the message queue is otherwise empty. This WM_PAINT causes OnPaint to be called.

Cheers,

Ash

Ms PowerPoint password protected File

MsmVc16-Jun-10 18:11

MsmVc

16-Jun-10 18:11

Hi All

How can i open Ms PowerPoint password protected file through code?I know password but i haven't idea how to open through code.

Please help me

Re: Ms PowerPoint password protected File

MsmVc16-Jun-10 23:48

MsmVc

16-Jun-10 23:48

Pleas give me advice?

Save to a file

thaiguy_md16-Jun-10 12:58

thaiguy_md

16-Jun-10 12:58

Hi!

Could you help me please...

I need to save data to file from here:

for (DWORD x = 0; x < pNotification->Count; x++)
                {
                    ASSERT(pNotification->aData[x].Type == JOB_NOTIFY_TYPE);
					//  ===++++++++++++++++++++++++++++++++++++++++++
                    CJobInfo *pJobInfo = NULL;

                    // if the job info item does not exist, create a new one
                    if (! m_mapJobInfo.Lookup(pNotification->aData[x].Id, pJobInfo))
                    {
                        pJobInfo = new CJobInfo(pNotification->aData[x].Id);

                        m_mapJobInfo.SetAt(pNotification->aData[x].Id, pJobInfo);
                    }

                    ASSERT(pJobInfo != NULL);
                    pJobInfo->UpdateInfo(&pNotification->aData[x]);

                    ::PostMessage(m_ThreadInfo.GetHwnd(), UDM_UPDATE_JOB_LIST, 0, 0);
                }

This is a code of Print monitoring program. Thank you!

Re: Save to a file

Rick York16-Jun-10 16:37

Rick York

16-Jun-10 16:37

You need to add :

pJobInfo->SaveDataToFile();

After the UpdateInfo() call.

Re: Save to a file

ThatsAlok16-Jun-10 23:55

ThatsAlok

16-Jun-10 23:55

Rick York wrote:
pJobInfo->SaveDataToFile();

nice onE!

cheers,
Alok Gupta
VC Forum Q&A :- I/IV
Support CRY- Child Relief and You

SetWindowsHookEx and Callback

AlmightyEdge16-Jun-10 10:26

AlmightyEdge

16-Jun-10 10:26

Hello,

Let me first start by telling you I have very little (read: none, ive read some parts in an ebook but..) experience with c++.
I'm trying to manage a callback to a more 'trusted' managed environment.

I'm trying to use SetWindowsHookEx(WH_CBT) on a specified application to monitor and alter window behavior.
I've created the HookProc in unmanaged c++ (see below) together with a Initialize function that takes as argument void* so I can call the function inside my managed application.
I pass the function of my managed application with Managed.getFunctionPointerforDelegate().
This seems to work.

However. If I hook the external process. (Read: Inject all of its threads seperately) it doesn't seem todo the callback to my managed application.
Winapi Override shows my unmanaged dll as being linked. (If I however can't find it through System.Diagnostics.Process.Modules)

The code:
The unmanaged part:

<FONT COLOR="#000099">#include "Hook.h"
</FONT><FONT COLOR="#999999">
// Callback...
</FONT><FONT COLOR="#FF6633">int</FONT><FONT COLOR="#663300"> (*</FONT>pfnCallback<FONT COLOR="#663300">) (</FONT><FONT COLOR="#FF6633">void</FONT><FONT COLOR="#663300">);</FONT><FONT COLOR="#FF6633">

void</FONT> Initialize<FONT COLOR="#663300">(</FONT>HANDLE retFunc<FONT COLOR="#663300">)
{</FONT><FONT COLOR="#FF0000">
	if</FONT><FONT COLOR="#663300"> (</FONT>retFunc<FONT COLOR="#663300"> !=</FONT> INVALID_HANDLE_VALUE<FONT COLOR="#663300">)
	{</FONT>

		pfnCallback<FONT COLOR="#663300"> = (</FONT><FONT COLOR="#FF6633">int</FONT><FONT COLOR="#663300"> (</FONT>_cdecl<FONT COLOR="#663300"> *) (</FONT><FONT COLOR="#FF6633">void</FONT><FONT COLOR="#663300">))</FONT> retFunc<FONT COLOR="#663300">;</FONT><FONT COLOR="#FF6633">
		int</FONT> a<FONT COLOR="#663300"> =</FONT> ThrowMessage<FONT COLOR="#663300">();</FONT><FONT COLOR="#FF0000">

		if</FONT><FONT COLOR="#663300"> (</FONT>a<FONT COLOR="#663300">==</FONT><FONT COLOR="#999900">5</FONT><FONT COLOR="#663300">)
		{</FONT>
			ThrowMessage<FONT COLOR="#663300">();
		}</FONT>
		ThrowMessage<FONT COLOR="#663300">();
	}
}</FONT><FONT COLOR="#FF6633">

int</FONT> ThrowMessage<FONT COLOR="#663300">()
{</FONT><FONT COLOR="#999999">
	// Do a callback..
</FONT><FONT COLOR="#FF0000">	return</FONT><FONT COLOR="#663300"> (*</FONT>pfnCallback<FONT COLOR="#663300">)(); 
}</FONT><FONT COLOR="#FF6633">

int</FONT> HookProc<FONT COLOR="#663300">(</FONT><FONT COLOR="#FF6633">int</FONT> nCode<FONT COLOR="#663300">,</FONT> WPARAM wParam<FONT COLOR="#663300">,</FONT> LPARAM lParam<FONT COLOR="#663300">)
{</FONT>

	ThrowMessage<FONT COLOR="#663300">();</FONT><FONT COLOR="#FF0000">
	return</FONT> CallNextHookEx<FONT COLOR="#663300">(</FONT>NULL<FONT COLOR="#663300">,</FONT>nCode<FONT COLOR="#663300">,</FONT>wParam<FONT COLOR="#663300">,</FONT>lParam<FONT COLOR="#663300">);
}</FONT>

The c# part:

<FONT COLOR="#990000">    public class</FONT> HookManager<FONT COLOR="#663300">
    {</FONT><FONT COLOR="#990000">

        private</FONT> GCHandle gch<FONT COLOR="#663300">;</FONT><FONT COLOR="#999999">               // Prevents garbage collection
</FONT><FONT COLOR="#990000">        private</FONT> delegate<FONT COLOR="#FF6633"> int</FONT> HookProc<FONT COLOR="#663300">();</FONT><FONT COLOR="#999999">   // Delegate that unmanaged api calls

</FONT><FONT COLOR="#990000">        private static</FONT> HookProc hookProc<FONT COLOR="#663300">;</FONT><FONT COLOR="#999999">   // HookProc variable ..
</FONT><FONT COLOR="#990000">        
        private static</FONT> Stack<FONT COLOR="#663300"><</FONT>IntPtr<FONT COLOR="#663300">></FONT> hookList<FONT COLOR="#663300"> =</FONT><FONT COLOR="#990000"> new</FONT> Stack<FONT COLOR="#663300"><</FONT>IntPtr<FONT COLOR="#663300">>();</FONT><FONT COLOR="#990000">

        public</FONT> HookManager<FONT COLOR="#663300">()
        {</FONT>
            hookProc<FONT COLOR="#663300"> =</FONT><FONT COLOR="#990000"> new</FONT> HookProc<FONT COLOR="#663300">(</FONT>HookEvent<FONT COLOR="#663300">);</FONT>

            gch<FONT COLOR="#663300"> =</FONT> GCHandle<FONT COLOR="#663300">.</FONT>Alloc<FONT COLOR="#663300">(</FONT>hookProc<FONT COLOR="#663300">,</FONT> GCHandleType<FONT COLOR="#663300">.</FONT>Normal<FONT COLOR="#663300">);</FONT>

            IntPtr managedReference<FONT COLOR="#663300"> =</FONT> Marshal<FONT COLOR="#663300">.</FONT>GetFunctionPointerForDelegate<FONT COLOR="#663300">(</FONT>hookProc<FONT COLOR="#663300">);</FONT>

            Poseidon<FONT COLOR="#663300">.</FONT>Initialize<FONT COLOR="#663300">(</FONT>managedReference<FONT COLOR="#663300">);
        }</FONT><FONT COLOR="#990000">

        public</FONT><FONT COLOR="#FF6633"> void</FONT> HookIt<FONT COLOR="#663300">(</FONT>Process hook<FONT COLOR="#663300">)
        {</FONT><FONT COLOR="#999999">
            // Now we will install hook
</FONT>            IntPtr hModule<FONT COLOR="#663300"> =</FONT> Win32<FONT COLOR="#663300">.</FONT>GetModuleHandle<FONT COLOR="#663300">(</FONT><FONT COLOR="#009900">"Poseidon.dll"</FONT><FONT COLOR="#663300">);</FONT>

            IntPtr ProcAddress<FONT COLOR="#663300"> =</FONT> Win32<FONT COLOR="#663300">.</FONT>GetProcAddress<FONT COLOR="#663300">(</FONT>hModule<FONT COLOR="#663300">,</FONT><FONT COLOR="#009900"> "HookProc"</FONT><FONT COLOR="#663300">);</FONT>

            ProcessThread<FONT COLOR="#663300">[]</FONT> threads<FONT COLOR="#663300"> =</FONT><FONT COLOR="#990000"> new</FONT> ProcessThread<FONT COLOR="#663300">[</FONT>hook<FONT COLOR="#663300">.</FONT>Threads<FONT COLOR="#663300">.</FONT>Count<FONT COLOR="#663300">];</FONT>

            hook<FONT COLOR="#663300">.</FONT>Threads<FONT COLOR="#663300">.</FONT>CopyTo<FONT COLOR="#663300">(</FONT>threads<FONT COLOR="#663300">,</FONT><FONT COLOR="#999900"> 0</FONT><FONT COLOR="#663300">);</FONT>

            foreach<FONT COLOR="#663300"> (</FONT>ProcessThread thread in threads<FONT COLOR="#663300">)
            {</FONT>

                IntPtr HHOOK<FONT COLOR="#663300"> =</FONT> Win32<FONT COLOR="#663300">.</FONT>SetWindowsHookEx<FONT COLOR="#663300">(</FONT>Win32<FONT COLOR="#663300">.</FONT>HookType<FONT COLOR="#663300">.</FONT>WH_CBT<FONT COLOR="#663300">,</FONT> ProcAddress<FONT COLOR="#663300">,</FONT> hModule<FONT COLOR="#663300">, (</FONT>uint<FONT COLOR="#663300">)</FONT>thread<FONT COLOR="#663300">.</FONT>Id<FONT COLOR="#663300">);</FONT>

                Console<FONT COLOR="#663300">.</FONT>WriteLine<FONT COLOR="#663300">(</FONT><FONT COLOR="#009900">"{0}, {1}, {2}"</FONT><FONT COLOR="#663300">,</FONT> hModule<FONT COLOR="#663300">,</FONT> ProcAddress<FONT COLOR="#663300">,</FONT> HHOOK<FONT COLOR="#663300">);</FONT>

                hookList<FONT COLOR="#663300">.</FONT>Push<FONT COLOR="#663300">(</FONT>HHOOK<FONT COLOR="#663300">);
            }
		}</FONT><FONT COLOR="#990000">

        public</FONT><FONT COLOR="#FF6633"> int</FONT> HookEvent<FONT COLOR="#663300">()
        {</FONT>

            Console<FONT COLOR="#663300">.</FONT>WriteLine<FONT COLOR="#663300">(</FONT><FONT COLOR="#009900">"Hookevent called!"</FONT><FONT COLOR="#663300">);</FONT><FONT COLOR="#FF0000">
            return</FONT><FONT COLOR="#999900"> 5</FONT><FONT COLOR="#663300">;
        }</FONT><FONT COLOR="#990000">

        private static class</FONT> Poseidon<FONT COLOR="#663300">

        {
            [</FONT>DllImport<FONT COLOR="#663300">(</FONT><FONT COLOR="#009900">"Poseidon.dll"</FONT><FONT COLOR="#663300">)]</FONT><FONT COLOR="#990000">
            public static extern</FONT><FONT COLOR="#FF6633"> void</FONT> Initialize<FONT COLOR="#663300">(</FONT>IntPtr callback<FONT COLOR="#663300">);
        }
	}</FONT>

Thanks already for reading this far. Does anyone have any idea this is ? Or suggestions?
I desperately try to get this to work. It's driving me nuts right now. D'Oh! | :doh:

Re: SetWindowsHookEx and Callback [modified]

Hristo-Bojilov16-Jun-10 11:14

Hristo-Bojilov

16-Jun-10 11:14

AlmightyEdge wrote:
I've created the HookProc in unmanaged c++ (see below) together with a Initialize function that takes as argument void* so I can call the function inside my managed application.

[EDIT]Why do you need to work around?In case it's not global hook you could use it directly from your .NET app but if it is you can't do it it using managed code[/EDIT]

I believe that this article is exactly for you.

Life is a stage and we are all actors!

modified on Wednesday, June 16, 2010 5:21 PM

Re: SetWindowsHookEx and Callback

AlmightyEdge16-Jun-10 12:48

AlmightyEdge

16-Jun-10 12:48

I thought that, in order to hook an external thread you needed to use unmanaged code Sigh | :sigh:

.
Thanks alot for the example, looks promising. I will try it out tomorrow Smile | :)

Re: SetWindowsHookEx and Callback

AlmightyEdge18-Jun-10 2:59

AlmightyEdge

18-Jun-10 2:59

Unfortunately it doesn't seem to work for external threads Frown | :(

Re: SetWindowsHookEx and Callback

Stephen Hewitt16-Jun-10 19:19

Stephen Hewitt

16-Jun-10 19:19

This whole area is a tricky subject. For starters the hook procedure for WH_CBT hooks that run in other processes must be in a DLL (which is injected into all the processes being hooked). Since you're trying to call a managed function from this DLL in the context of every hooked process, the managed code must also (somehow) be injected along with the DLL that contains the hook procedure. This could lead to a common problem which can occur when trying to build component systems using .NET: trying to load multiple versions of the CLR into a single process. See In-Process Side-by-Side[^] for details on this.

Perhaps you'd be better using some kind of IPC instead of a direct function call.

Steve

Re: SetWindowsHookEx and Callback

AlmightyEdge18-Jun-10 3:00

AlmightyEdge

18-Jun-10 3:00

I thought a direct function call would be the fastest.
You got any suggestion for IPC?

Re: SetWindowsHookEx and Callback

Stephen Hewitt21-Jun-10 15:04

Stephen Hewitt

21-Jun-10 15:04

A direct function call would be the fastest, but direct function calls can only occur within a process. Since you're hooking other processes this could cause problems.

Steve

wrap the wininet dll

alto16-Jun-10 7:41

alto

16-Jun-10 7:41

I need to create a dll that will wrap Microsoft wininet.dll
The idea is to install this Dll instead of the regular one in all the organization workstation and add some adjustments to few actions in the wininet.dll, especially logs
Is it possible? I need to do it so the application that use the wininet.dll wont be noticed the different.

Re: wrap the wininet dll

ThatsAlok16-Jun-10 23:57

ThatsAlok

16-Jun-10 23:57

alto wrote:
I need to create a dll that will wrap Microsoft wininet.dll
The idea is to install this Dll instead of the regular one in all the organization workstation and add some adjustments to few actions in the wininet.dll, especially logs
Is it possible? I need to do it so the application that use the wininet.dll wont be noticed the different

little difficult task but achievable! you need to program all the function exposed by WinInet with same order and need to deploy it over wininet!

cheers,
Alok Gupta
VC Forum Q&A :- I/IV
Support CRY- Child Relief and You

Re: wrap the wininet dll

Moak17-Jun-10 3:43

Moak

17-Jun-10 3:43

Probably a bad idea... thinking about how many legal scenarios there are to change wininet.dll.

Chat in Europe Java | [Coffee]

Now with 24% more Twitter

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.