Implementing a single login for three websites in PHP?
问题 I have a network for three websites that related. - site1.domain.com - site2.domain.com - site3.domain.com Currently, each submdomain has ~100 accounts in three separate databases. They login separately for each domain. I'd like to create site0.domain.com that lets them authenticate against one database, and then automatically log the user in to each site as they visit them. I'm not too sure how to do this. I've heard terms thrown around like Open ID and Federations and Single Sign On but I