I want to know best practice about CI3 security.

Hi Vimal.

Look this:

http://www.codeigniter.com/user_guide/ge...urity.html

Always use $this->input->post('value',TRUE); The TRUE is important for prevent XSS Injections.

David

Using good validations is not better then this ?

Yes!! I Forgot!

You can use the form validation http://www.codeigniter.com/user_guide/li...ation.html