You should also note that by maintaining a separate user-login system, you have two databases you need to keep synchronized, making sure to add, modify and delete users in both.

Although it is clearly your own business, I suggest to take a look at fully using WordPress as your userdatabase. I do that on linklaunder.com (which is not active at the moment, unfortunately), where I use a few plugins to ensure a double-opt-in system where users actively agree to the disclaimer, privacy policy, etc. This is through the use of the plugin “Register Plus”.

It is very easy to use a bit of php-code in your template files, to use WordPress to process user-level, and provide individual user data to logged in users.

Just my suggestion, let me know if you need some help, should you choose to go that direction.

Thank you for visiting, and leaving a comment!

I will use it to integrate a blog using Wordpress to my site, I’ve already have a user login authentication, and don’t to use wordpress login

I’m populating my site users table to wp_user table

Do you think I would have a security issue if I use it for this purpose?

Best of luck with the code, glad it helped