Can we use single sign on for diffrent Form Authentication Sites?

I have 2 different websites开发者_Go百科

-> webgrants.com

->calgrants.com can be accessed directly or from webgrants

there is link provided for calgrants.com in Webgrants.com so how can i validate the credentials of user when they click on the link provided. how can i do this .urgent please

There might be better ways to do it, but off the top of my head you can do this: Assuming they have access to the same(or a common) database you create a table of userId and ticket. Whenever a user wants a redirection to other website, you create a random value(ticket) and assign that value to the user and store this pair into the database. You add this ticket to address of the other website, as a parameter. Other website checks the table for that 'ticket' and authenticates the user.