How create demo setup of window application

 
 1. try to allow he can access your application  30 time  or 50 times  etc.
     by storing start Application count. using Global.asax file. after that you can block your Application.


2. store your date in Encrypted formate and check when he Start application compare Date from date store in database.
   if difference more than 30 then block Application.
  
  

It is pretty easy to crack if users have access to the database file.

Information about installation time must be encrypted or gathered from alternative sources (multiple sources if possible - e.g. constants placed in source to verify valid date ranges, then new application setup would be built and uploaded every ten days or so).

Use your imagination, do whatever seems to be working. If any element of verification fails it means that user has been playing with application files and the system in order to prevent your protection. For example, you can append data to some file your application is using so that its length is divisible with installation day in year - then use file's length to double-check installation date read from the system. Don't be shy when coding protection...

Zoran

Hi Sharad,

You can create  Table1 with 1 field "ED"  in MS Access or sql server. 

   con = odal.openconnection();

                com = new OleDbCommand("select * from Table1", con);

                oda = new OleDbDataAdapter(com);

                OleDbCommandBuilder obul = new OleDbCommandBuilder(oda);

                DataSet ds = new DataSet();

                oda.Fill(ds, "Table1");

                OleDbDataReader odr = com.ExecuteReader();

                if (ds.Tables["Table1"].Rows.Count >= 2)

                {

                    MessageBox.Show("Your demo period has expired !!!\nPlease contact to your software consultant.", "System Manager", MessageBoxButtons.OK, MessageBoxIcon.Error);

                    this.Close();

                }

                else if (odr.HasRows)

                {

                    odr.Read();

                    DateTime SD = Convert.ToDateTime(odr[1]);

                    DateTime ED = Convert.ToDateTime(DateTime.Now.Date.ToString("dd/MM/yyyy"));

                    TimeSpan TS = ED.Subtract(SD);

                    odr.Close();

                    odr.Dispose();

                    if (TS.Days > 30)

                    {

                        OleDbCommand ocom1 = new OleDbCommand("insert into Table1 values('2',#" + Convert.ToDateTime(ED).ToShortDateString() + "#,'ED')", con);

                        ocom1.ExecuteNonQuery();

                        MessageBox.Show("Your demo period has expired !!!\nPlease contact to your software consultant.", "System Manager", MessageBoxButtons.OK, MessageBoxIcon.Error);

                        this.Close();

                    }

                }

It becomes quite difficult if you want to make it good. But simple solutions are possible - based on idea that application only tests date/time and user would have to change system date to continue using it, which people often do not do because it's very annoying.

To protect application and make it with limited work, you can build two versions of the application. One with limitation should test date/time on many places in code. Additionally, you can limit features (e.g. cannot create a document with more than 100 elements in it, etc.). In that case you literally build two applications. One with physical limitations, another without them. Then distribute the limited application. It ensures that user won't be able to crack it in place, because the application doesn't contain both limited and unlimited code.

Simple example with documents: Application stores document elements as List; in limited application implement the same feature as element[100]. Then it becomes very hard to crack application to receive more than 100 elements, because it hasn't allocated list for them.

Similar is with dates - check them on many places, so that cracking becomes very difficult. In legal version don't check date ever. Do not check date conditionally (like if (!registered) testdate()). Then hacker would only search for registered flag and for the testdate function in order to crack the application in a simple way.

Rule of thumb when protecting applications. Make protection code messy as much as you can. Use different patterns to check for registration. Making it hard for hacker to clean the binaries from that pieces of code is the best protection against them.

Hope these guidelines help.

Zoran