[RBH]

First of all the credits for this idea go to orgy who maked this thread:
https://hackforums.net/showthread.php?tid=545488
I advice you to read that thread because that will explain this functions.

I made a 2 functions to do this.

The first one is MD5get:

Code

Public Function Md5Get() As String
  Dim MD5 As New System.Security.Cryptography.MD5CryptoServiceProvider
  Dim Data() As Byte
  Dim hash() As Byte
  Dim strData As String = IO.File.ReadAllText(Application.ExecutablePath)
  Data = System.Text.Encoding.UTF8.GetBytes(strData)
  hash = MD5.ComputeHash(Data)
  MD5 = Nothing
  Dim strOutput As New System.Text.StringBuilder(hash.Length)
  For i As Integer = 0 To hash.Length - 1
    strOutput.Append(hash(i).ToString("X2"))
  Next
  Return strOutput.ToString().ToLower
    End Function

That function is used by the program to get the md5 hash of the executable.

The 2th function is to check if the md5 hash is right, i did this in combination with a online hosted txt file.

Code

Public Function Md5Check() As String
  Dim md5 As String
  Dim wc = New System.Net.WebClient
  Try
    md5 = wc.DownloadString("") ' < You Url here with the MD5 textfile: www.example.com/md5.txt
  Catch ex As Exception
    MsgBox("The txt file is not there or you have no internet access")
    Application.Exit()
  End Try

  If md5 = Md5Get() Then
    MsgBox("Valid")
  Else
    MsgBox("Edited")
  End If
    End Function

THIS TOO FUNCTIONS ME BE USED IN COMBINATION OTHERS THEY WONT WORK.

You may mod this functions to you needings but you need to give credits ;)

i made this little program using the md5get function to find the md5 of a other file:
[IMG]http://i32.[censored].com/30ux193.png[/IMG]
virusscan
Spoiler (Click to View)File Info

Report date: 2010-07-16 16:22:38 (GMT 1)
File name: GetMd5.exe
File size: 18432 bytes
MD5 Hash: ec8852739e0fc55b89264b02184c0f26
SHA1 Hash: cdffa7899cb7ba0773642da375b1069b10218eb3
Detection rate: 0 on 16 (0%)
Status: CLEAN

Detections

a-squared -
Avast -
AVG -
Avira AntiVir -
BitDefender -
ClamAV -
Comodo -
Dr.Web -
F-PROT6 -
G-Data -
Ikarus T3 -
Kaspersky -
NOD32 -
Panda -
TrendMicro -
VBA32 -

Scan report generated by
NoVirusThanks.org

downloadlink (source included):

Code

http://www.mediafire.com/?xgi86f4a81tm19c

I made a example project too with md5check and md5get (my url is included for md5 hash checking):

Code

http://www.mediafire.com/?isar64k595gz9iw

[Vordal]

What stops them just editing this, as well as whatever else they plan on changing after recompiling your application?

[RBH]

What do you mean vordal?
This functions are created to use in other programs the md5 changes when somebody trys to hex edit your program and then the program will not be useable.

[Vordal]

I mean, say your App is HWID protected. So I make some edits, and remove the HWID. Now, thanks to this function, that cracked App won't run. Well done. However, if I am able to remove the HWID Function, there is no reason I can't do the same to this function.

[Tate]

What do you mean vordal?
This functions are created to use in other programs the md5 changes when somebody trys to hex edit your program and then the program will not be useable.

He means whats stopping them from editing:

PHP Code


<?php 
if MD5Hash = MyMD5Hash then
End if 


to

PHP Code


<?php 
if MD5Hash = MD5Hash then
End if 


Anyways, good tutorial, this could be useful.

[Neroxan]

He means whats stopping them from editing:

Writing your own simple encryption algorithm and encrypting the details, seeing how you should already be doing that for the clients hwid number anyways...

[RBH]

I mean, say your App is HWID protected. So I make some edits, and remove the HWID. Now, thanks to this function, that cracked App won't run. Well done. However, if I am able to remove the HWID Function, there is no reason I can't do the same to this function.

You only need to temporary disable the function and do you edits and then update the web file with the new md5 file and you can run the program again?

[Orgy]

Those of you saying "What if they crack it?"

Sure, but that can be said with any method. What if you don't offer HWID protection, you'd like to make a free version, and you don't want users binding shit to your program? Boom, this solves that problem, since binding it would create a different hash.

You could step this up by also checking filesize, etc.

This will work really well against skids that just like to bind their cybergates or plaguebots to shit.

And with the proper obfuscation, it will hinder crackers

[nathan72389]

um.... what prevents me from changing your app to simply skip all your little md5 bullshit checks?

if md5 = ok then form1.show.. blah! we can bypass that so that regardless it will always be correct

if username found on online DB.. blah... we can skip that function also.

[Orgy]

um.... what prevents me from changing your app to simply skip all your little md5 bullshit checks?

if md5 = ok then form1.show.. blah! we can bypass that so that regardless it will always be correct

if username found on online DB.. blah... we can skip that function also.

See my post above. The typical skid wouldn't know how to do that

[RBH]

um.... what prevents me from changing your app to simply skip all your little md5 bullshit checks?

if md5 = ok then form1.show.. blah! we can bypass that so that regardless it will always be correct

if username found on online DB.. blah... we can skip that function also.

blah.. This is just BLah example, you know BLAH!
just to give people a idea BLAHBLUB!

BLAH DRUNKEN REDNEK

[¶_¶]

But it's not a binder protector. If we bind the file with another it will run.

[RBH]

@q_q yes you are right but it will atleast warn you ;)

[¶_¶]

Yes, thanks for the idea. :]

[GyroErbin0]

how about doing it like this ;)

Code

Public Sub Md5Check()
  Dim md5 As String
    md5 = "Already calculated Md5 of your app"' < Calculated MD5 of your app :) ( NO INTERNET CONNETION :) )
  End Try

  If Not md5 = Md5Get() Then
   Me.Close
  End If
    End Sub