PHP Single Sign-on issues, new help

PHP Single Sign-on problem, new help
Learn PHP a week, the company to give me a PHP Single sign-on function, seek the help of master, try to give me some source code

Problem: Www.a.com (program written in Java), has implemented to www.b.com (PHP, is the DZ X2 code) site of the single sign-on function;
Now want to use Www.b.com (PHP written, is the DZ X2 code) login to Www.a.com (Java program) Single Sign-on function

At present, I have Baidu Google some things, but a lot of can not understand

And I used some of the DZ forum, but how to write to the Www.a.com site session and Cookie (WWW.A.COM user login is session and Cookie saved)

------Solution--------------------
Cookies:
Setcookie (Cookiename,cookievalue);

SESSION:
Session_Start ();
$_session[name]=value;
------Solution--------------------
Two sites share memcache,session save inside.
------Solution--------------------
Explore

Well, I'm not sure what I'm talking about upstairs. I am now Java program can implement a one-way login to the PHP forum, but how to implement a one-way login to Java program with PHP, is the problem, the source

------Solution--------------------
Two-way encryption to pass the data, pass the past after decryption, if the information is correctly set to the login state.

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