So I just cracked my first CrackMe and found out how the program computes the registration number and now I wanna write a keygen for it.

 

What program should I use to write the keygen and could anyine get me started on the code?

 

The algorithm the CrackMe uses to create the correct keygen is:

 

Get hex value of each letter in username

Add each letter in hex together

Multiply the value by 539

Output as decimal

 

Thanks to anyone who can help

VB .NET 2010

Public Class frmKeygen

    Private name As String = ""

    Dim character As Long = 0

    Private sum As Integer
    Private Sub txtInput_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtInput.TextChanged

        name = txtInput.Text

        Try

            For i = 0 To name.Length - 1

                character = character + Asc(name.Substring(i, 1))

            Next

            character = character * 539

            txtOutput.Text = character.ToString

        Catch ex As Exception

            MessageBox.Show("The result of multiplication is too high.", "Try less characters for the name.", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)

        End Try
    End Sub

End Class

Project.7z

Keygen.7z

C# .Net 3.5 - Console App - compile with SharpDevelop/VisualStudio/MonoDevelop/...

using System;

using System.IO;

using System.Linq;

using System.Reflection;
namespace Keygen

{

	class Program

	{

		static void Main( string[] args )

		{

			if( args.Length == 0 )

			{

				string thisExe = Path.GetFileName( Assembly.GetExecutingAssembly().GetName().Name );

				Console.WriteLine( "Use {0}.exe USERNAME", thisExe );

				return;

			}
			// first prog argument

			string username = args[ 0 ];
			// call/invoke Generate-Method

			decimal key = Generate( username );
			// show result, Output as decimal

			Console.WriteLine( "Key: '{0}'", key );

		}
		// easy to understand Method

		static decimal Generate( string username )

		{

			decimal result = 0;
			//Get hex value of each letter in username

			foreach( char letter in username )

			{

				//Add each letter in hex together

				result = result + (byte)letter;

			}
			//Multiply the value by 539

			result = result * 539;
			return result;

		}
		// pro variant

		static decimal ProGenerate( string username )

		{

			return username.Aggregate<char, decimal>( 0, ( current, letter ) => current + (byte)letter ) * 539;

		}

	}

}

Howdy.
Did Someone Forget other none .NET Languages?

 

Here is one for Delphi 7 (this is just the function that generates the key)

function MakeMyKey(UserName: string): string;var  intCounter, intHolder: Integer;  strFinalKey: string;begin  if (Length(UserName) < 1) then  begin    ShowMessage('Hey Cutie, Don' + 't be ' + 'shy :(' + sLineBreak +      'Please give me a Name');  end  else  begin    intHolder := 0;    for intCounter := 1 to (Length(UserName)) do    begin      intHolder := intHolder + Ord(UserName[intCounter]);    end;    strFinalKey := IntToStr(intHolder * 539);    Form1.edtSerial.Text := strFinalKey;  end;end;

Attached is the Keygen and its Full Source.

 

Lukesc1993 Keygen.zipLukesc1993 Src.zip

Howdy.

Did Someone Forget other none .NET Languages?

 

Did you mean this?

#include <iostream>#include <string>using namespace std;int main(){    int suma, lungime;	string nume;	cout << "Simple translation to C++ by GIV\n";	cout << "Please enter your name: "<<endl;    cin >> nume;    lungime = nume.length();	suma = 0;for (unsigned int i = 0; i < nume.size(); i++){     suma += nume[i];}cout << "The final calculus is:"<<endl;		cout << suma*539 << endl;     system("pause");    return 0;}

C++.7z

Did someone forget about the non-high-level languages?

	Generate proc hWnd:HWND
		invoke	        GetDlgItemText, hWnd, IDC_NAME, addr NameBuffer, 17   ; Cap name length to 17

		mov		edi,offset NameBuffer

		invoke	        lstrlen,edi

		mov		esi,eax

		xor		ecx,ecx

		xor		eax,eax
		cmp		esi, 01h   ; Jump if no name entered

		jl		BADERROR
		xor		eax, eax

		xor		edx, edx
		@@:
			mov		dl, byte ptr [NameBuffer + ecx]

			add		eax, edx
			inc 	        ecx

			cmp		ecx, esi

			jnz		@b
		mov		ecx, 21Bh    ; 21Bh = 539d

		mul		ecx
		invoke	        wsprintf, addr SerialBuffer, addr FormatControl, eax

		invoke	        SetDlgItemText, hWnd, IDC_SERIAL, addr SerialBuffer
	BADERROR:
		xor		eax, eax

		ret
	Generate endp

Lukesc1993.zip

Edited November 9, 201410 yr by Office Jesus

 Did someone forget about script language? :worthy:

username = raw_input('Name -->')

serial = 0

for i in username:

	serial+=ord(i)

serial*=539

print serial

keygen.py.tar.gz

Edited November 14, 201410 yr by Levis

So many options to choose from

Why not AutoIT? lol

#include <MsgBoxConstants.au3>
Example()

Func Example()

    Local $i, $output

	Local $Input = InputBox("Input","", "", "")
	For $i=0 to StringLen($input)

		$output = $output + Asc(StringMid($input,$i,1))

	Next
	$output = $output * 539
    MsgBox($MB_SYSTEMMODAL, "", $output)
EndFunc   ;==>Example

I am to late.

No new code from my side

only a bit shorter ASM code of Office Jesus

Generate proc hWnd:HWND
	invoke	GetDlgItemText, hWnd, IDC_NAME, addr NameBuffer, 17   ; Cap name length to 17

	.if 	eax

		lea	edi, NameBuffer

		xor	eax,eax

		and 	edx,0

		.repeat	

			mov	dl,byte ptr [edi]

			add	eax, edx	

			inc 	edi

		.until byte ptr[edi] == 0

		imul	eax,eax,21Bh

	invoke	wsprintf, addr SerialBuffer, addr FormatControl, eax

	invoke	SetDlgItemText, hWnd, IDC_KEY, addr SerialBuffer

	.endif 
	ret
Generate endp

of course it can be done shorter.

(btw. i was to lazy, so i used OfficeJesus own code snippet.)

 

@Lukesc1993 Crackme name?