I have three different websites and I want to create a single entry point for all of them but how?

We are creating three different websites using asp.net but for the user part we wa开发者_开发知识库nt to implement an approach so that each user only need to create an account in any of these three sites but use the same account in other websites too. here is what I've suggested :

create a useracount.website.com server then put the sql server there and implement core user account library there such as (creating/editing/etc...)

whenever a visitor needs to have an account or needs to login into out sites then we will redirect him to the useracount.website.com address and he/she should login from that point. and for the maintaining the user's states I've suggested to using cookies.

and all of these scenarios should be implemented by asp.net and sql.

please let me know with best approach cause I feel mine is not that good specially the cookie part.

cheers.

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