public void validate( String pinInput ) 
    {
        if ( secretPin.equals(pinInput) )
        {
            this.authenticated = true ;
            System.out.println( "Valid Pin" ) ;
            System.out.println("Now please choose a payment method.");
        }
        else
        {
            this.authenticated = false ;
            System.out.println( "Invalid Pin" ) ;
            System.out.println("Please type pin again");
        }
    }