cross domain - Single Sign On (SSO) using JWT -

i have read several articles sso not find answer in mind. have scenario below:

scenario:

• my company wants have sso mechanism using jwt.
• company has 2 different domains abc.com abc , xyz.com xyz.
• also there masterdomain manages clients authentication.
• user x wants log in abc @ first.
• abc sends credentials masterdomain , masterdomain authenticates user create signed jwt in order send abc.
• abc keeps jwt in cookie.
• after while if login abc attempted @ same computer, system not ask credentials , automatically login user.

question:

if user tries open page in xyz domain, how system understand user loggedin before? mean xyz domain cannot reach cookie of abc has jwt. information should sent xyz indicates user x trying login?

thanks in advance

you can store jwt authentication token in cookie / localstorage of intermediate domain connected home page using iframe

scenario

• abc sends credentials masterdomain , masterdomain authenticates user create signed jwt in order send abc.

• abc masterdomain keeps jwt in cookie.

• after while if login abc attempted @ same computer, system not ask credentials , automatically login user.

finally when user enters in second domain xyz, jwt recovered masterdomain storage using iframe, , automatically login user

cors not problem because masterdomain.com have access storage , communication between iframes allowed if origin , destination recognized (see http://blog.teamtreehouse.com/cross-domain-messaging-with-postmessage)

to simplify development, have released opensource project cross domain sso jwt @ https://github.com/aralink/ssojwt