C#
 private string EnryptString(string strEncrypted)
    {
        try
        {
            byte[] b = System.Text.ASCIIEncoding.ASCII.GetBytes(strEncrypted);
            string encryptedConnectionString = Convert.ToBase64String(b);
            return encryptedConnectionString;
        }
        catch
        {
            throw;
        }
    }

    private string DecryptString(string encrString)
    {
        try
        {
            byte[] b = Convert.FromBase64String(encrString);
            string decryptedConnectionString = System.Text.ASCIIEncoding.ASCII.GetString(b);
            return decryptedConnectionString;
        }
        catch
        {
            throw;
        }
    }

VB.NET



 Private Function EnryptString(ByVal strEncrypted As String) As String
     Try
      Dim b As Byte() = System.Text.ASCIIEncoding.ASCII.GetBytes(strEncrypted)
      Dim encryptedConnectionString As String = Convert.ToBase64String(b)
      Return encryptedConnectionString
     Catch
     Throw
     End Try
  End Function
 
  Private Function DecryptString(ByVal encrString As String) As String
      Try
         Dim b As Byte() = Convert.FromBase64String(encrString)
         Dim decryptedConnectionString As String = System.Text.ASCIIEncoding.ASCII.GetString(b)
         Return decryptedConnectionString
       Catch
       Throw
       End Try
   End Function