You can encrypt your connection string to a database. Let me rephrase that: you should encrypt data connections. Here is an example of encrypting a connection string and decryprting a connection string.

Create the Connection String in your App.Config:

connectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source???;DatabaseName;"            providerName="System.Data.OleDb" /

Form Code:

private void EncryptConnectionString()        {            System.Configuration.Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);            string provider = "DataProtectionConfigurationProvider";            ConfigurationSection connstrings = config.ConnectionStrings;            connstrings.SectionInformation.ProtectSection(provider);            connstrings.SectionInformation.ForceSave = true;            config.Save(ConfigurationSaveMode.Full);        }        private void DecryptConnectionString()        {            System.Configuration.Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);            ConfigurationSection connstrings = config.ConnectionStrings;            connstrings.SectionInformation.UnprotectSection();            connstrings.SectionInformation.ForceSave = true;            config.Save(ConfigurationSaveMode.Full);        }        private void EncryptButton_Click(object sender, EventArgs e)        {            EncryptConnectionString();        }        private void DecryptButton_Click(object sender, EventArgs e)        {            DecryptConnectionString();        }