Phone Book in C# - CodeProject®

Introduction

Some days ago, I lost my cellphone. All of my contact numbers were in the cellphone and I lost them. Miraculously I found my cellphone, but I decided to create a phone book application to store my contacts. This application was written in C# and LINQ. I used an XML file to store contacts and I encoded them with the 3DES algorithm to protect them.

Application Features

Live Search

You could search your contacts as Live.

Multi Users

The application can have several users. Each user can just see his/her contacts.

Password Reminder

If you want to use this feature, you have to enter a valid User name and Password of your SmptClient in C# code.
Also, you can enter your Gmail's user name and password. You have to enter them in Forgets the password region in UserForm.cs.

try
{
    NetworkCredential loginInfo = new NetworkCredential("username", "password");
    MailMessage msg = new MailMessage();
    msg.From = new MailAddress("sth@gmail.com");
    msg.To.Add(new MailAddress(user.First().Attribute("Email").Value));
    msg.Subject = "Phonebook Password";
    msg.Body = "Yours Password = " + password;
    msg.IsBodyHtml = true;
    SmtpClient client = new SmtpClient("smtp.gmail.com");
    client.EnableSsl = true;
    client.UseDefaultCredentials = false;
    client.Credentials = loginInfo;
    client.Send(msg);

    MessageBox.Show("Your password has been sent to your email", "Email sent",
    	MessageBoxButtons.OK, MessageBoxIcon.Information);
}
catch (Exception ex)
{
    MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}

At last, compile the project with new data and use it.

Security

To protect contacts, I've used .NET 3DES classes.

//Base on : http://msdn.microsoft.com/en-us/library/system.security.cryptography.
	//tripledescryptoserviceprovider.aspx
public static void EncryptToFile(String Data, String FileName, byte[] Key, byte[] IV)
{
    try
    {
        // Create or open the specified file.
        FileStream fStream = File.Open(FileName, FileMode.Create);

        // Create a CryptoStream using the FileStream
        // and the passed key and initialization vector (IV).
        CryptoStream cStream = new CryptoStream
				(fStream, new TripleDESCryptoServiceProvider().
        	CreateEncryptor(Key, IV), CryptoStreamMode.Write);

        // Create a StreamWriter using the CryptoStream.
        StreamWriter sWriter = new StreamWriter(cStream);

        // Write the data to the stream
        // to encrypt it.
        sWriter.WriteLine(Data);

        // Close the streams and
        // close the file.
        sWriter.Close();
        cStream.Close();
        fStream.Close();
    }
    catch (CryptographicException e)
    {
        Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
    }
    catch (UnauthorizedAccessException e)
    {
        Console.WriteLine("A file access error occurred: {0}", e.Message);
    }
}

public static string DecryptFromFile(String FileName, byte[] Key, byte[] IV)
{
    try
    {
        // Create or open the specified file.
        FileStream fStream = File.Open(FileName, FileMode.OpenOrCreate);

        // Create a CryptoStream using the FileStream
        // and the passed key and initialization vector (IV).
        CryptoStream cStream = new CryptoStream
				(fStream, new TripleDESCryptoServiceProvider().
        	CreateDecryptor(Key, IV), CryptoStreamMode.Read);

        // Create a StreamReader using the CryptoStream.
        StreamReader sReader = new StreamReader(cStream);

        // Read the data from the stream
        // to decrypt it.
        string val = sReader.ReadToEnd();

        // Close the streams and
        // close the file.
        sReader.Close();
        cStream.Close();
        fStream.Close();

        // Return the string.
        return val;
    }
    catch (CryptographicException e)
    {
        Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
        return null;
    }
    catch (UnauthorizedAccessException e)
    {
        Console.WriteLine("A file access error occurred: {0}", e.Message);
        return null;
    }
}

No one can see your data in the XML file, because it is encoded. I suggest to change the Key and the Vector and use your own ones in TripleDES.cs. These are default Key and Vector:

public static byte[] ByteKey = 
	new byte[] { 65, 20, 35, 105, 249, 97, 242, 87, 163, 127, 124, 121,
	73, 225, 209, 103, 5, 198, 68, 221, 122, 14, 224, 2 };
public static byte[] IV = new byte[] { 160, 175, 98, 111, 208, 167, 177, 23 };