I want to know best practice about CI3 security.

From http://www.codeigniter.com/user_guide/ge...-filtering

XSS filtering should only be performed on output. Filtering input data may modify the data in undesirable ways, including stripping special characters from passwords, which reduces security instead of improving it.

Passing TRUE to the second parameter of $this->input->post() passes your input through the XSS filter, which should not be done.

On output, you can pass your data (or individual values from your data) through $this->security->xss_clean() as needed.

Bonfire

Practical CodeIgniter 3
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