Generating Unique Key(Finger Print) for a Computer for Licensing Purpose

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Introduction

For licensing purpose according to me the best way and secure way is to generate an unique key for client's machine and providing a corresponding license key for that key. For this purpose you can take help of the unique id of client's computer's motherboard, BIOS and processor's. When you get these IDs you can generate any key of your preferable format.

Year ago I found a very handy and useful code in C# by searching net to get these IDs. And its serving me perfectly so far. Thanks to the original author of the code.

I added some additional code to generate a 128 bit key of a machine. The output is a nice looking key in hexadecimal format (eg. 4876-8DB5-EE85-69D3-FE52-8CF7-395D-2EA9)

Suggestions

I have few suggestions on this regard.

*) Generate key from only Motherboard, Processor and BIOS. Since user normally doesn't chagne these parts.

*) Don't use MAC ID, Graphics Card ID AND Disk ID. Since its very common to change these devices.

*) It takes significant time to get IDs of devices. So make the finger print generating fucntion static and save it in a static variable so that it generates the key only for one time in the whole application.

The Code

Here is the class. The code in the region "Original Device ID Getting Code" is from the original author.

using System;
using System.Management;
using System.Security.Cryptography;
using System.Security;
using System.Collections;
using System.Text;
namespace Security
{
/// <summary>
/// Generates a 16 byte Unique Identification code of a computer
/// Example: 4876-8DB5-EE85-69D3-FE52-8CF7-395D-2EA9
/// </summary>
public class FingerPrint
{
 private static string fingerPrint = string.Empty;
 public static string Value()
 {
     if (string.IsNullOrEmpty(fingerPrint))
     {
         fingerPrint = GetHash("CPU >> " + cpuId() + "\nBIOS >> " + biosId() + "\nBASE >> " + baseId()
                     //+"\nDISK >> "+ diskId() + "\nVIDEO >> " + videoId() +"\nMAC >> "+ macId()
                              );
     }
     return fingerPrint;
 }
 private static string GetHash(string s)
 {
     MD5 sec = new MD5CryptoServiceProvider();
     ASCIIEncoding enc = new ASCIIEncoding();
     byte[] bt = enc.GetBytes(s);
     return GetHexString(sec.ComputeHash(bt));
 }
 private static string GetHexString(byte[] bt)
 {
     string s = string.Empty;
     for (int i = 0; i < bt.Length; i++)
     {
         byte b = bt[i];
         int n, n1, n2;
         n = (int)b;
         n1 = n & 15;
         n2 = (n >> 4) & 15;
         if (n2 > 9)
             s += ((char)(n2 - 10 + (int)'A')).ToString();
         else
             s += n2.ToString();
         if (n1 > 9)
             s += ((char)(n1 - 10 + (int)'A')).ToString();
         else
             s += n1.ToString();
         if ((i + 1) != bt.Length && (i + 1) % 2 == 0) s += "-";
     }
     return s;
 }
 #region Original Device ID Getting Code
 //Return a hardware identifier
 private static string identifier(string wmiClass, string wmiProperty, string wmiMustBeTrue)
 {
     string result = "";
     System.Management.ManagementClass mc = new System.Management.ManagementClass(wmiClass);
     System.Management.ManagementObjectCollection moc = mc.GetInstances();
     foreach (System.Management.ManagementObject mo in moc)
     {
         if (mo[wmiMustBeTrue].ToString() == "True")
         {
             //Only get the first one
             if (result == "")
             {
                 try
                 {
                     result = mo[wmiProperty].ToString();
                     break;
                 }
                 catch
                 {
                 }
             }
         }
     }
     return result;
 }
 //Return a hardware identifier
 private static string identifier(string wmiClass, string wmiProperty)
 {
     string result = "";
     System.Management.ManagementClass mc = new System.Management.ManagementClass(wmiClass);
     System.Management.ManagementObjectCollection moc = mc.GetInstances();
     foreach (System.Management.ManagementObject mo in moc)
     {
         //Only get the first one
         if (result == "")
         {
             try
             {
                 result = mo[wmiProperty].ToString();
                 break;
             }
             catch
             {
             }
         }
     }
     return result;
 }
 private static string cpuId()
 {
     //Uses first CPU identifier available in order of preference
     //Don't get all identifiers, as very time consuming
     string retVal = identifier("Win32_Processor", "UniqueId");
     if (retVal == "") //If no UniqueID, use ProcessorID
     {
         retVal = identifier("Win32_Processor", "ProcessorId");
         if (retVal == "") //If no ProcessorId, use Name
         {
             retVal = identifier("Win32_Processor", "Name");
             if (retVal == "") //If no Name, use Manufacturer
             {
                 retVal = identifier("Win32_Processor", "Manufacturer");
             }
             //Add clock speed for extra security
             retVal += identifier("Win32_Processor", "MaxClockSpeed");
         }
     }
     return retVal;
 }
 //BIOS Identifier
 private static string biosId()
 {
     return identifier("Win32_BIOS", "Manufacturer")
     + identifier("Win32_BIOS", "SMBIOSBIOSVersion")
     + identifier("Win32_BIOS", "IdentificationCode")
     + identifier("Win32_BIOS", "SerialNumber")
     + identifier("Win32_BIOS", "ReleaseDate")
     + identifier("Win32_BIOS", "Version");
 }
 //Main physical hard drive ID
 private static string diskId()
 {
     return identifier("Win32_DiskDrive", "Model")
     + identifier("Win32_DiskDrive", "Manufacturer")
     + identifier("Win32_DiskDrive", "Signature")
     + identifier("Win32_DiskDrive", "TotalHeads");
 }
 //Motherboard ID
 private static string baseId()
 {
     return identifier("Win32_BaseBoard", "Model")
     + identifier("Win32_BaseBoard", "Manufacturer")
     + identifier("Win32_BaseBoard", "Name")
     + identifier("Win32_BaseBoard", "SerialNumber");
 }
 //Primary video controller ID
 private static string videoId()
 {
     return identifier("Win32_VideoController", "DriverVersion")
     + identifier("Win32_VideoController", "Name");
 }
 //First enabled network card ID
 private static string macId()
 {
     return identifier("Win32_NetworkAdapterConfiguration", "MACAddress", "IPEnabled");
 }
 #endregion
}
}

Upcoming Code

Later I'll show how I generated the license key from the unique machine key. The license key contains many information like the Product Name, License Start Date, End Date and the Key.

Download the complete source code.