Question:What are the three methodology of authentication? 

Question:What are the PHP authentication variables? 

Question:
Breifly explain the following functions:
explode()
list()
fwrite()
fputs()
fclose()
md5()
rand()
uniqid()
substr()
filter_var()
 

Question:How to send http authentication header with php header() function? 

Question:What are the four lines we need to write to .htaccess file to restrict any folder in the webserver?