php - Deny user to login and alow him after 1 hour -

I'm trying to block the user to log in (because it's temporarily restricted) and it's again Allow to login

Now I do not know how I should do this, I think I should use htaccess to deny the user, but I do not know how it is allowed to join again.

I am using an XML file as a database (I am the issuant of security), here is an example of my XML file:

    
 As you can tell that I use MD5 for password.  
 So I temporarily want to restrict the user for one hour, then how can I do this to activate my account? / P>  
 
 
 You can add a tag and save it at the time of the restriction. Then check the time in the login script and when you are less than one hour difference between the current time and the restricted time, you will see the message "You are banned".